1998 Opel Corsa Enging cuts out under braking

Hello, I have a 98 1l opel corsa 57000 mls. When the engine gets warm ( say 20 mins driving ) the engine cuts out under braking, roundabout, traffic lights etc, and wont restart until the engine has cooled again (10-20 mins) I have replaced the lambda sensor today but the problem persisted on the way home.
Any help would be greatly welcomed
Alan