If it's a weekend, driving will be a lot easier, but almost always the M25 is stop start, gridlock and standstill.Tune into "Capital radio" or radio 2. But if I could suggest, you pick up the anti clockwise direction, going past the M1 turning, then Heathrow, then it might be a bit easier than going clockwise and towards London as it's much nearer the M4 junction, but you could go round to the M3, still anti clockwise and cut across Hampshire.