Stopped at some lights, noticed blue lights coming, lights changed so pulled out of the way, moved off again and into second, and the engine just redlined for no reason, with a cloud of smoke and a soot line behind, dipped the clutch and the revs dropped, engine still running so continued on my way gently, so far its not done it again in 20 miles

So any ideas as to what could have happened

Check your front grille - does it have a red light oscillating behind it, going left and right?

 

(Lame reference to Knight Rider and KITT, and your car having a mind of its own.  I'll get me coat...)

Edited 28 March, 201412 yr by JakeBlade

Had you recently topped up the engine oil? Sometimes, on another brand, they had trouble with excess engine oil getting into the engine, and the engine would effectively run on its own lubricant. As it was uncontrolled the rev limiter had no effect either.