I believe it would give children an extra hour wind-down time after school and give them a chance to attend un-floodlit outdoor sports activities that they do in the summer. Especially in run down urban areas.
At present we have 5 months of unnecessarily early dark evenings. As it stands at the moment we have to wait 3 months after the winter solstice till the clocks change back again, whereas we change them 2 months before the WS. At the very least can we have we change the clocks to BST at the end of February to even out the time spent in early darkness either side of Christmas.