There is no best time for the M25 - Some times are less bad than others. ( well apart from midnight to 6am )

Unfortunately there is no route that I can recomend to avoid it.

My personal preference would be M11 south, M25 Clockwise and over the Dartford Crossing. M25 south and around to the M3. M3 south and west, A303 west of Basingstoke to Salisbury. (A303 is not a bad road)

I can not recomend the M4 out of London at that time of the day.

My self, when crossing from West to East, I use various "Rat runs" including the A25, but you would hit the town traffic if you start at 15.30 hrs - And unless you know the "Rat Runs" you will get lost.

A Caution or two

1/. - The M11/M25 junction was not built for speed. When the signs suggest 40MPH they mean it. I had difficulty controlling an "Astra" the first time I used this junction at 60 ish.

2/. Have a handfull of coins handy for the tolls on the Dartford Crossing. Say £1 and 10p coins. (Sorry I can't remeber what the current toll is)

3/. The M25/A21/M26 - Junction is a B****t First of all the split between the A21 and M25 is the reverse of what you expect. Keep to the left hand lane. When the M26/M26/A21 merge about three quarters of a mile later The M26 feeds in from your left as a down slope/grade, and watch out for heavy foriegn lorries running in from your left. Some of them still think that thier on the Autobahn, and have the right of way.

4/. Stop at Clackets Lane Services for a comfort stop. You wont have another chance till just before Basingstoke - and if you are caught in a traffic jam !!!!

5/. After Clacketts Lane try and keep out of the left hand lane. Some of the junctions between there and the M3 junction carve the left hand lane off, and given the standard of driving on the M25 you may have difficulty in changing lanes at the last moment.

Enjoy your trip

Gareth

(who spent more years than he cares to remember as a Claims Inspector in that area - and those roads)