Hello mate, had the same problem this morning, made me an hour and a half late for work!! If it happens again get underneath from the drivers side about half way along the car and get a 2ltr coke bottle full of hot water and squeeze it really hard, firing the water up towards the exhaust heatshield. Worked for me this morning but don't use the handbrake again until it dries out or warms up otherwise it just sticks on again worse than before (as I found out when I went to leave work this evening!!)
Lee