Flat out speed of ex-Formula One driver? (9)
I believe the answer is:
prostrate
'flat' is the definition.
(laying flat)
'out speed of ex-formula one driver?' is the wordplay.
I cannot really see how this works, but
'speed' could be 'rate' (the speed at which something happens) and 'rate' is found within the answer.
'of' could be 'o' and 'o' is found in the answer.
This explanation may well be incorrect...
Can you help me to learn more?
(Other definitions for prostrate that I've seen before include "no longer able to stand" , "Lying face downwards" , "Flat" , "Totally exhausted" , "Prone" .)