Just returned from a round trip to York, just over 700 miles through Friday motorway traffic.

The Merc returned an average of 55.7 mpg on std BP Diesel through a mix of m'way cruising 85'ish, stop start traffic Jams.....43 miles x 2 M25/ M23 and about 30 miles of mixed town traffic.

I wasn't trying to fuel efficient and kept ahead of most o the traffic, but that economy on a bog standard Cd220d is fantastic....the gauntlet's down for my annual trip to Germany - with cruise control and autobhans I reckon I can cover door to door (about 800 miles) on a tankfull with some to spare