If by "cont" you mean continental, my favorite is Brasserie St. Quentin on Brompton Road (I think) in Knightsbridge. I've taken several business associates there. None was ever disappointed in the choice. Not too expensive, either. Dinner reservations are a must, even on weekdays, unless you arrive before 7 pm (they open at 6:30) and will promise to be out by 8:30.

Boudin Blanc comes highly recommended by someone who's shown good judgment in other cases, but I've never eaten there myself.

The Chez Gerard chain, if you must have French and you have no other options.