Batch update timestamp records to correct timezone
To adjust timestamp values for the difference between any two given time zones, use the AT TIME ZONE construct twice in a row. See:


Ignoring time zones altogether in Rails and PostgreSQL


Assuming you want to adjust all timestamps after the begin of British Summer Time (BST) at '2018-03-25 01:00':

UPDATE tbl
SET    ts = ts AT TIME ZONE 'BST' AT TIME ZONE 'UTC'
WHERE  ts &gt;= '2018-03-25 01:00';


Of course, in your particular example you might just subtract an hour:

...
SET    ts = ts - interval '1 hour'
...