Meet the 'M' division monsters you might have wished for, but never got to own.

BMW's M brand is the original premium high performance road car range. Developed from Motorsport, its purpose is clear: take regular production cars and hone them into high-performance specials.

Sure, the first BMW M car was the 1978 M1, a very exotic range-topper out of reach for many. BMW soon followed it up with something more accessible, though. The first 'M' saloon was the M 535i, but the first 'real' M was the 1985 BMW E28 M5, complete with 286hp BMW M1 engine.

Since then, there have been many more examples of classic M cars - but did you know there have been several more potentially great M cars that never reached production?

Stored in the secret lair of BMW's M HQ are rows of one-off M cars, created to test the water, but never given the green light. Some of these, in hindsight, could have been true classics, too.

MSN Cars was treated to a special tour of the BMW M HQ, to check out these secret BMW M cars up close.

Read on to see the M cars that never were - and let us know which you think represent a missed opportunity for BMW M...

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