Do the reports state it 1am BST then an hour later 1am GMT?
When the clocks change it happens at 1am GMT.
Because BST is an hour ahead of GMT between the last Sunday in March and the last Sunday in October, the change happens at 2am technically you go from 1:59:59 BST to 1:00:00 GMT.
The concept of British Summer Time is meaningless outside of Britain so I don't know what "reports" you are referring to.
There is a reason for why such a change occurs at such an unGodly hour of the morning, 1am, but I forget what it was.
While British Summer Time might be meaningless outside Britain, the concepts of adjusting clocks by an hour in Spring and Autumn is fairly (totally?) widespread. Central European Time (GMT+1) adjusts to Central European Summer Time (GMT+2) for example. The concept of Daylight Saving Time is fairly well known.
While checking this post I found reference to Dublin Mean Time - abolished in something like 1916, which put Southern Ireland 25 minutes behind GMT! How bizarre is that? ISTR from GCSE History lessons that until the railways came and a ntaional timetable was required, places like Bristol would be 8 minutes behind London, but I didn't know about the Dublin thing. According to
Wikipedia, there are many places with off-the-hour timezones. Caracas is UTC-4:30, Tehran is UTC+3:30, Delhi is UTC+5:30, Kathmandu is UTC+5:
45
(that has to be the oddest), Adelaide and Darwin are UTC+9:30.
ISTR the Delhi thing is why Asia Today (1430GMT?) on BBC World always had to start on the half hour precisely (whereas other back-half hours didn't start at any specific time...) to meet their top of the hour...