Concepts and prototypes : MG ADO21 (1969-1970)

Work on the promising MG ADO21 began in Abingdon in 1968, following the formation of BLMC.

The E-Series powered mid-engined sports car had the looks of a Ferrari, but was passed over in favour of the Triumph Bullet.

MG ADO21: The MGF, some 20 years too soon

The very sleek body of the ADO21 clothed an interesting set of mechanicals: a mid-mounted E-Series engine, five-speed gearbox and Hydrolastic suspension

The MG ADO21 came about following the formation of BLMC in 1968. The reasoning was clear: the MG EX234 had been consigned to history, and the MG range was rapidly ageing. There was also, of course, the small matter of where MG would fit in the new empire given that Triumph was now a part of that same corporation, and offered a range of competing models…

The Engineers at Abingdon were keen to move on from the EX234 and develop a sports car to replace the MG Midget (and Triumph Spitfire). In mid-1969, Abingdon began work on a car that would eventually result in the MG ADO21. The idea that the new sports car would be mid-engined fell into that brief, as it was a layout that the Italians had embraced.

Very quickly, the mechanical package was defined: an E-Series engine/transmission package would be mounted amidships, and the suspension system would be a semi-independent layout employing Hydrolastic displacers, a set-up used in the ill-fated EX234.

MG ADO21: suspension of disbelief

According to David Knowles’ book, MG: The Untold Story, the rear suspension was particularly sophisticated: it was a ‘de Dion suspension arrangement, a sophisticated semi-independent system well-suited to mid- and rear-engined cars…’

Under lead Engineer, Roy Brocklehurst, the ADO21 took shape at Abingdon and, although there were some packaging problems inherent with the tall E-Series engine, the project moved along quite quickly.

(Above and below) These pictures were produced by Paul Hughes, who worked from an original sketch by Harris Mann. First shown in David Knowles’ book, MG: The Untold Story, these pictures reveal that the MG ADO21 project was designed to look unlike any MG that had come before – in fact, there were many design cues shared with Ferrari’s Dino 206GT. The look was extremely adventurous, but so was the mechanical layout


Using the E-Series engine in the ADO21 meant that the entry-level version would be a 1500cc model, but with the potential to expand to the 2227cc E6 engine (with little modification), through the 1748cc version of the E4.

It was not lost on anyone that these engine capacity options struck into the heart of the MGB’s market sector – and, therefore, the ADO21 was moving away from its original brief as the corporation’s smallest sports car.

Harris Mann's ADO21 proposal.
Harris Mann’s ADO21 proposal was less striking than Paul Hughes’ but looked more easily productionised.

MG ADO21: packaging problems

The E4 Maxi engine’s height meant that the rear deck lid was on the high side, leading to a narrow rear window, flanked by a pair of buttresses. Looking at the styling sketches and subsequent clay model, the height of the rear deck was cunningly disguised, and the clean lines at the front of the ADO21 were maintained at the rear.

Another problem was the transmission. Not so much the gearbox, but the change linkage – the 1968 Austin Maxi used a three-cable arrangement, which resulted in the famously poor change action.

In the ADO21, this arrangement would also be used, but with even longer cables, necessitated by the mid-engined layout. One can only imagine what the change quality would have been like!

Engineering drawing of the ADO21

Like the Triumph Lynx/Bullet projects that were concurrently being worked on at Canley, the Abingdon/Cowley ADO21’s existence was well documented. There was the pressing matter of how best to serve the needs of the corporation as a whole and, because the ADO21 had become a MGB replacement, it was emerging as a direct competitor with Triumph’s Bullet.

By late 1970, the full-size ADO21 model had been prepared and decisions about its future needed to be made.

Political intrigue and in-flighting take their toll

The MG ADO21 featured a transverse mid-mounted E4-Series engine and used Hydrolastic suspension. It was cancelled in December 1970 and made way for what was to emerge as the Triumph TR7


According to David Knowles, the ADO21’s situation was somewhat bizarre: initially, there was a great deal of pressure to complete the ADO21 in the early days, but then that pressure, ‘simply evaporated’.

In his book, he goes further: ‘After nine months of concentrated effort on the project, Rod Lyne says that work on the ADO21 simply petered out: “I never got told it had definitely been canned: I was simply told to leave it on the side in order to get on with other urgent work.”

‘The sole prototype languished in a corner of the development shop, gathering dust, until Austin Morris Engineering Director Charles Griffin – who had supported the venture in the first place – paid one of his occasional visits, about 12 months after work had stopped on the vehicle. “You might as well chop it up”, was his instruction, so the entire car was destroyed.’

The MG ADO21 is viewed by management

A full-sized clay model of the Paul Hughes and Harris Mann-styled ADO21 was viewed by BLMC management on 3 November 1970. By this time, Spen King and Mike Carver had visited the USA in order to find out what it was that the Americans wanted in the company’s upcoming sports cars. They were told that the Americans wanted simplicity and reliability and so it is easy to see why management decided to favour the conventional Triumph Bullet over the more advanced ADO21.

Messrs King and Carver’s findings clearly influenced British Leyland’s Corporate Sports Car Policy and so the ADO21 was effectively doomed… Indeed, formal confirmation of this can be found in the minutes of the management meeting to view the ADO21, which included this passage: ‘The wooden model of ADO21 was viewed in the studio. The front end was unanimously admired, but there were some reservations about the rear end. However, in view of the Corporate Sports Car Policy, it was decided that no more work is to be done on this programme.’

‘I never got told it had definitely been canned: I was simply told to leave it on the side in order to get on with other urgent work.’ – Rod Lyne

However, looking at the styling models, it is easy to see why BLMC management requested that the Triumph Bullet should be restyled by Harris Mann, and that car be injected with some of the ADO21’s dramatic style. The spirit of the ADO21 lived on – it can be said – in the MGF, which shared that car’s engine layout and fluid suspension.

Yes, the ADO21 was that far ahead of its time!


[Editor’s Note: Written with reference to MG: The Untold Story by David Knowles and MG by McComb by F. Wilson McComb.]

Keith Adams


  1. Obviously someone had been looking at a Ferrari Dino, but what strikes me most is …………. I’ve never seen a better design for perfectly slicing off pedestrians’ legs

  2. Hehe- I was thinking the same thing.

    Advertising tagline could have been ‘Your Grandmother wouldn’t like it…’

    Quite a pretty car, but I think it would have aged rapidly, and I really can’t warm to the idea of an E Series powered sportscar with that gearbox…

    Not only that, but I suspect it would not have sold well in the US- as having such a low front would have made a rather unpleasant mess in collision with an oversized US pickup truck.

  3. Would the front bumper even have met US regulations?

    Their specific height bumper regs meant the MGB got rubber suspension stops to raise the front. Canadian Minis ended up with a ridiculous bumper halfway up the grille.
    Citroen had to stop selling cars there, as with the suspension settled the car bumper would be too low (though they got around this in the 90s with the anti-sink mechanism, and seem to be abandoning hydropneumatic suspension systems).

  4. That needle nose is absurdly long. It would surely have been shortened if the project had continued towards produciton.

  5. The narrow-angle 2-litre V4 / 3-litre V6 or even the 143-170 hp 2.2 Rover DOHC 16v fuel-injected 4-cylinder as well as the V6 versions of the Rover V8 would have been more suitable to power ADO21 compared to the proposed E4/E6 units.

    However tempting a V8 would be it seems appropriate for ADO21 to live up to its entry-level Dino-esque looks by remaining at best a 4/6-cylinder 2-seater sportscar, especially if ADO21 is somehow produced alongside the 3-seater Rover P9.

  6. “However, looking at the styling models, it is easy to see why BLMC management requested that the Triumph Bullet should be restyled by Harris Mann, and that car be injected with some of the ADO21’s dramatic style.”

    I’d much rather that Bullet had made it into production without any of the Harris Mann wedginess! I think the original Michelotti Bullet/Lynx proposals look really stylish

    • It would have been interesting to see how the styling of original Michelotti Bullet/Lynx proposals end up evolving over time from the mid/late-70s beyond with the absence of Harris Mann’s influence.

      Could see the rear of the Bullet/Lynx proposals resembling the TR7-derived Lynx prototype, though not sure whether it would have paired well with the family front-end look Triumph were then planning with the Bullet/Lynx proposals along with the Michelotti styled Puma prototype.

  7. Here’s an interesting thought. Take the aerodynamica bodywork and put this chassis underneath it. E series 1500, B series 1800TC with rod change, E series 2200 in twin and triple carb. Great handling and good performance with more showroom appeal. And there’d be enough room for a 4 seater too, judging by the position of the PA rear axle.

  8. Such an excellent looking sports car and would have addressed the ageing design and relatively low performance of the smaller MG and Triumph sports cars. Yet it wasn’t to be due to be and the MGB and Spitfire continued through the seventies and had become very old fashioned and not particularly fast( 100 mph was nothing by 1979) when they were axed.

  9. Am trying to figure out how the engine range would have worked with a production version of ADO21 in terms of performance, as with standardized Special Tuning kit a 1.5-2.2-litre E-Series would have roughly put out around 83-125 hp while enlarged 1.6-2.4 E-Series versions would have roughly put out around 89-134 hp.

    A 2-litre O-Series would have probably put out around 105-127 hp and that is without mentioning the turbocharged O-Series prototype engines that were said to put out around 140-160 hp, though an O-Series ADO21 would partly depend on the competitiveness / success of the E-Series ADO21 as well as how well executed the gearbox layout is.

    An interesting engine that could have potentially benefited ADO21 was a little-known V6 anticipated to be in the shelved ADO77 project, assuming it is not simply a V6 version of the Rover V8 or an engine from another carmaker.

  10. Engines are a moot point. The best Leyland engine I think must be the V8 3.5 liter ex Buick.
    Another good engine is the k series 1.8 liter. It is a good performer in the F type and quite a nice engine, was it not for the tendency to blow head gaskets.
    The Chinese has apparently fixed this, and the longlivity of that slightly modified engine seem to be unquestioned. Had Rover done their homework with this engine, they would most likely still be in business.
    The KV6 engine is nice, but nothing special, lacks torque, uses troublesome plastics and is not economical.

    • The Rover V8 was already planned to be used on the ill-fated mid-engined Rover P9 (aka Rover Alvis P6BS) project, hence why it is worthwhile to speculate on suitable alternative engines for ADO21 had it reached production.

  11. Pretty little thing, isn’t it?
    Relatively simple concept too, later used to great effect by Fiat and Toyota, and much later by MG Rover itself of course…
    Would have caused a few seizures among the flat-cap MG brigade who had harrumphed at the new MGB only a few years before – when that had unitary construction, permanently attached hood, wind-up windows and external door handles – good heavens, whatever next!!

  12. Reading this story brings up some big questions:

    1.If Spen King went to the States and upon hearing from dealers BL decided that the new corporate sports car would be conventional, why had Rover previously planned the P9 a mid engine sports car? Was this not designed for the US market or had Rover not done any research?
    2.So why did FIAT go ahead with mid engine sports cars in the X1/9 and later Lancia Monte Carlo, which America was the main market (both were designed to replace the 124)?

    • Think the P9 was envisioned as more of a supercar than a sportscar thus would have likely commanded a higher price, compared to the more accessible ADO21 and what became the TR7 prior to the latter moving upmarket.

      The X1/9 was conceived to replace the 850 Spider, while the Montecarlo was conceived to replace the 124 Sport Spider. As for the reason why Fiat opted for the mid-engine layout for sportscars with the US being one of the main markets, the following is a guess on my part though it might be because Fiat were apparently looking to move upmarket with the mid-engine layout at the time being perceived as exotic and typically seen on more expensive cars.

      • The 124 spider ended up outliving the Lancia Montecarlo, and MASSIVELY outselling it.

        And of course the default small sports car of the last 35 years is the front engined RWD MX5…

  13. I believe X1/9 and X1/20 were designed midengined to make easy use of the FWD drivetrains form the Fiat 128 and Lancia Beta, just like the MGF later did with the Metro drivetrain.

    • You are right. A pity Fiat did not continue with the mid-engined sportscars prior to or even in place of the later Fiat Barchetta, a mid-engined Montecarlo replacement with turbocharged Integrale style 4WD sounds much more appealing then the Lancia Hyena.

      As for the X1/9, not sure whether it would have been worthwhile for Fiat to develop an Uno-based mid-engined sportscar to replace X1/9 or revamp the X1/9 to feature the 1.3-1.4 Uno / Punto turbo engines and possibly more potent NA versions of the SOHC unit.

  14. The X1/9 was a decent seller, but no better than the TR7 really, while the Montecarlo was a bit of a commercial flop really.

    ADO21 certainly would have added glamour to the showrooms, though to be it looks more suited as a low production flagship halo model, rather than a mainstream coupe/convertible like the Triumph alternatives proposed at the time.

    • Fiat offloaded the X 1/9 to Bertone, the car’s designer, in 1982, as the struggling company needed to devote its resources to the Uno and replacing the Mirafiori, and the X 1/9 was seen as peripheral and expensive to produce. The Bertone versions moved more upmarket and they did produce a version with leather seats and electric windows.

  15. We may need to ignore the ‘benefit of hindsight’ with some of our comments. The front of this car is surely no worse in terms of being a leg chopper than many a Ferrari, Iso, Lamborghini, DeTomaso, Lancia or Fiat of the period. We simply didn’t think of such things in those days so pointless to criticise now?

  16. Thinking about it further in terms of ADO21 being a Midget replacement, perhaps a properly developed EA111-like version of the compact 9X/10X engine would have been more suitable instead of the E-Series?

    After all Issigonis already managed to develop a 1.5 4-cylinder version for one of his Gearless Mini prototypes, then there is the 75 hp 1275cc 6-cylinder where a tuned 100 hp version was later fitted into an MG Metro (with Issigonis envisaging the engines having the potential to feature twin-cams). A more EA111-like 9X/10X would mean the maximum 4-cylinder displacement would be a 1.6 (see mk3 Polo GTi and Lupo GTi), with potential for a 2.4 6-cylinder (however unlikely the latter would be).

    The similarly mid-engined Healey WAEC prototype (derived from a pair of ADO16 subframes with disc brakes all round) as well as the Towns TXC Tracer both featured A-Series engines though it seems both were heavy and under-powered (until the concept was refined and implemented years later on the MGF), the mid-engined GTM Coupe kit-car being arguably the more successful of the mid-engined BMC/Mini/Metro-derived sportscars.

  17. Assuming the E-Series was significantly less tall (like the later S-Series) and capable of being enlarged to 2-litre 4-cylinder (plus a 3-litre inline-6) as well as featuring a similar non-Maxi end-on gearbox arrangement as would appear on transverse mid-engined sportscars like the Fiat X1/9, Lancia Montecarlo and Lancia Stratos, ADO21 might have been more feasible and had the knock-on effect of also making the Gilbern T11 viable.

    It would have been even better for ADO21 if like the mid-engine ADO16-derived Healey WAEC, 128-derived X1/9 and Beta-derived Montecarlo was itself derived from a more suitable car already in production as opposed to being a bespoke model.

    Apart from the E6-powered ADO17/X6/ADO71, the only other examples of a transversely-mounted FWD inline-6 would appear to be the Daewoo Magnus / Tosca as well as a few Volvos using their inline-6 version of the Modular and SI6 engines.

    Provided ADO21’s engine / gearbox arrangement (with end-on instead of in-sump gearbox) had been sorted out, how would the same limitations that afflicted transversely-mounted FWD inline-6 layout (e.g. reputedly wide turning circle, etc) have potentially impacted a transversely-mounted RWD inline-6 sportscar like ADO21 with virtually the opposite layout?

    The Lancia Stratos itself utilized a transversely-mounted Ferrari Dino V6 (with a Maserati V6 considered as a possible alternative until Ferrari relented), while there was sort-lived talk of the production Lancia Montecarlo featuring a V6 at one point though it is difficult to see where a 6-cylinder ADO21 would fit into the mix between the two. Meanwhile the large and more potent original BMW M1’s inline-6 was AFAIK only mounted longitudinally.

  18. This car is classic BMC, when you first look at it you think “if only” but when you dig into it you realise it would have been an interesting but somewhat dreary car and a financial money pit like the Austin 3 Litre. Because it has two fundamental flaws,

    One is the size, weight and limited power potential of the E series engine in both 4 and 6 cylinder, Fiat X19 or Lancia Montecarlo this was not going to be, instead it would have been embarrassed by the performance of a VW Scirocco let alone offered anything more to justify the inconvenience of its mid-engine layout.

    Two however is probably the ultimate killer of this car, MG sports car viability was based on the ability to take the “cooking” components of a modest British saloon and wrap them up in a “sporty little frock” which could then be sold to Americans with a healthy profit. Until reading this I had always assumed that like the MG-F, which sat basically on two Rover Metro front ends, this was sitting on two Maxi front ends. However instead it has a sophisticated and unique and given the limited production volumes very expensive rear end (we do not know what the front was, but I suspect it was also bespoke) and this would have thus made the car financially unviable.

    • How very true. All in all probably a rare just, even wise decision by BL management not to pursue this concept.

  19. Very much agree, there are many flaws to this prototype that make it unviable unlike the similarly mid-engine 1975 Nissan AD-1 concept.

    It was also too hasty IMHO to consign EX234 to history and not apply the ADO21 styling to the former, as was the case with the Triumph Bullet to become the TR7 and thereby have EX234 directly replace the B, Midget and Spitfire without conflicting with the TR7. In essence an earlier plan of what was brought up in the History : The secret Product Plans page for sports car model in spring 1983 to replace the Midget and Spitfire.

  20. Having the Maxi gearchange would be a big killer for the ADO 21. People who drove sports cars wanted a crisp, slick gearchange, not a rubbery, ponderous change that would ruin the driving experience, even if the five speeder would cut engine revs and improve economy. Also the 1500cc E series was a less than satisfactory engine.
    I’d think for the ADO21 to succeed would be to carry over existing, proven technology from within British Leyland, such as the 1500 cc Triumph engine and the B series found in the MGB, and use the B series as the performance model, with the Triumph 1500 for the entry level ADO21. Also fitting overdrive to the transmission would be far better than using the Maxi five speeder.

  21. I could see how this could have worked, in the US.

    Six cylinder versions of the E-series only, 2.2 and 2.6, automatic and air conditioning as standard, and normal suspension (coils and wishbones at the front, Chapman struts or similar at the rear) in place of the unconventional and shade-tree-mechanic hostile hydrolastic stuff.

    Think of it like an early version of the Pontiac Fiero – a cheap-but-sporty two seater commuter car. If only they could have made it to be reliable!!

    • Rather than being based on the Maxi, it would have instead made more sense for the MG ADO21 in de-restricted ~150 hp or so six-cylinder form to have been created from the Rover P9.

      Especially had the P9 gone into production and shared much with the then upcoming SD1, which made use of both the V8 and in South Africa the E6.

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