Sir Lindsay Hoyle might be best known for keeping MPs in line in the House of Commons - but he managed to clock off from the day job on Friday with a visit to Big Ben.
The Speaker of the House lent a hand as work began to put the world-famous clock back to Greenwich Mean Time (GMT) in time for Sunday.
While the nation looks forward to an extra hour in bed - parliament's clockmakers will be embarking on a 24-hour mission to ensure politics keeps to time.
Big Ben is one of 2,000 timepieces throughout the Palace of Westminster and across the Parliamentary Estate that will need to be adjusted to take account of the time change this autumn.
This year is significant as it will be the first time Big Ben will be put back to GMT since the scaffolding came down from the Elizabeth Tower following an £80m restoration project spanning five years.
Sir Lindsay said the clock change "will herald a new beginning" for the iconic London landmark.
"While the rest of us are tucked up in our beds, our own father time, Ian Westworth and the team will be clocking up eight miles changing our parliamentary clocks, including the one we love the most - the Great Clock of Westminster - better known as Big Ben.
"For the first time in five years, they will be working with the clock's completed original, Victorian mechanism, so it is a significant final moment in the conservation of this magnificent timepiece."
People will only be aware that the Great Clock is being changed to GMT when the lights go out on its four dial faces at 10pm on Saturday evening.
"This is so people looking up do not wonder why the hands are going round and get confused," said parliamentary clock mechanic, Alex Jeffrey, 35.
Big Ben stopped chiming when the restoration project began in 2017, though the bongs have returned for special events.
Sir Lindsay said Big Ben's bongs "will once again return to our national soundtrack on Armistice Day and Remembrance Sunday, striking 11 times to mark the start of the two minutes' silence".
The five-year restoration of the Elizabeth Tower involved extensive scaffolding, 500 workers and ended up running £51m over budget.
The clock's iconic dials have been restored to their original colour - Prussian blue - after experts discovered the shade under layers of black paint. The lights behind the clock-face were once powered by gas but have now been switched with energy efficient LEDs, while seven hundred pieces of stone have been replaced - all of them carved on site.
The tower was designed by Charles Barry and Augustus Pugin and completed in 1859 during the reign of Queen Victoria, when many were obsessed with watches and the standardisation of time.
It was damaged during the Blitz, by a century-and-a-half of London pollution and weather, and by the discovery of asbestos.