Surrey grapes

We acquired this grape vine when we moved in 25 years ago and always assumed that the weather here just wasnt warm enough to produce edible (or drinkable) grapes. Bearing in mind that we have done nothing over the years to encourage them, we have never had any great hope of a useable crop! however this year the grapes are edible - but only if you stick to the really black ones!!! Is this global warming??