During WW2 did British troops often wear berets rather than helmets in combat situations?
Alternatively, I could imagine that the berets are just over represented in the media because British helmets of the time were rather silly looking.
EDIT: I couldn't find links, but the first examples that spring to mind are band of brothers, inglorious basterds and one of the call of duty games.
One of the more popular (as in oft broadcast films) is A Bridge Too Far, simply due to it's all-star cast.
The british there are Paratroops, hence the maroon berets.
There is even the one scene where they risk their lives to collect a supply canister parachuted to them, and it's full of berets.
In 1943 MG Browning granted a battalion of the US Army's 509th Parachute Infantry Regiment honorary membership in the British Parachute Regiment and authorized them to wear British maroon berets, so these might be the guys who you see in the other movies or games.
Could you give us some examples? Maroon berets were the signature headdress of the British Parachute Regiments of WWII. It could very well be that the depiction you've seen have all been of paratroopers.