Description Ultra-rare 6.3 V12 AMG with 444bhp; believed to be one of only around 26 made; two owners from new; advisory-free MOT; cost the equivalent of £400k new; a unicorn Merc at a Shetland pony guide price Mercedes has long been a towering giant among car manufacturers, with vast reserves of cash and engineering expertise that dwarfed the resources of most other makes.

To keep ahead of the pack, they would always have an exotic flagship model to showcase just what could be achieved when the gloves were off and budgets were unlimited.

In the late-1990s that model was the C215 Coupe, a rolling laboratory of exotic materials and high-tech driver aids, some of which might trickle down to more mainstream models several years later, and some of which were just too expensive to replicate at scale.

At the top of the tree sat the CL600 V12, a silent giant in a Savile Row suit which had a base price of around £85,000 but could easily cost up to £100,000 if every option box was ticked (eq...