When is the best time to severely prune an apple tree minus creating growth, I live contained by the north of scotlan ...
Answers: i agree with adjectives the above but would add that if you want to noticeably reduce the size of your tree it would be best to do it over a 3 year interval so new regrowth isn't so stimulated and to trim down stress.
Any pruning of an apple tree will stimulate growth. I always pune my apple trees surrounded by February just formerly they start to think in the region of growing. I live in Cambridgeshire so you may want to presume about hasty to mid March (it really does depend on the weather though - don't prune in frosty conditions). I attended a day's apple pruning course a few years ago within February and they were pruning their full orchard at this time.