Hate to be pernickety
, but the change should have been made at 2 am BST, which should then have become 1 am:
"The time at which summer time begins and ends is given in the relevant EU Directive and UK Statutory Instrument as 1 a.m. Greenwich Mean Time (GMT). In practice*, in the UK, summer time starts when 00:59:59 UTC is followed by 02:00:00 BST (British Summer Time) and it ends when 01:59:59 BST (when it occurs for the first of two times separated by one hour) is followed by 01:00:00 UTC."
Quoted from NPL