Greece is now saying Germany owes them 279 billion euros for war reparations - which coincidentally works out as the 240b EU bail out they received plus a nice few billion extra on top.
Maybe we can sue the Romans for coming over here 2000 years ago and invading us.
Building London, Chester etc, building all their roads, bringing us wine, bringing us rabbits, building Hadrian's wall, leaving all their roman houses to dig up on Time Team years later.
Of course we can also sue them for killing all the druids (and quite a few other people in our country at the time).