What date do the clocks go back in 2017, why do they change and when will they go forward again?

EACH year our clocks go forward an hour in March and back in October as British Summer Time (BST) starts and finishes.

The changes result in longer daylight hours in the summer and a whole 60 minutes extra in bed come October. But what date to the changes take place and why does it happen? Here's all the info…