Mix together the the crushed biscuits and melted butter then press into a 10″ cake tin. Loose bottom tins are easier for serving but I don't have one in my van and find my silicone one works just fine.
Combine the condensed milk, cream, lemon juice and grated rind. Just a little stir, nothing more is needed. Pour on top of the biscuit base and leave in fridge or a cool place to set.