 In 1927, clocks were advanced by an hour from first Sunday in November to the first Sunday in March.This proved unpopular, so the "Summer Time Act 1928" revised this to a "half"-hour shift from 14 October 1928 (second Sunday) to 17 March 1929 (third Sunday), then the "Summer Time Act 1929" permanently fixed this half-hour shift to run from the second Sunday in October to the third Sunday in March every year.In 1933, the period was extended from the first Sunday in September to the last Sunday in April.