Crime that brings a heated reaction (5)

I believe the answer is:

arson

I'm a little stuck... Click here to teach me more about this clue!

'crime' is the definition.
(crime of illegally starting a fire)

I can't explain the rest of the clue.

(Other definitions for arson that I've seen before include "Incendiary crime" , "serious offence" , "Roans (anag)" , "Malicious fire-lighting" , "Iniquitous behaviour" .)

I've seen this clue in the Evening Standard.

Want a hint initially instead of a full solution? Install my app