Any passenger carrying airport must have it's own fire fighters (in varying quantities and with assorted requirements for the equipment they must have) to comply with the terms of it's license based on the category of airport it is and all that is set out in CAP 168.
A GA field also has it's own first response fire team and as far as I know that is part of it's license requirements. No doubt they would expect to call for support off the local County Brigade if things got out of hand.
Personally I would feel more at risk (on a statistical basis) in a car on the M25 with no fire brigade to put out the conflagration and release me than in the Cherokee at Fairoaks where at least there is somebody with a truck and a few extingushers at hand.
