A historic cinema clock is turning back time – and sometimes stopping it.

The clock at the Duke Of York’s in Preston Circus, Brighton, had functioned faultlessly for 99 years until recently.

Time has taken its toll on the inner workings and the clock is now lagging an hour behind and sometimes stops altogether.

Duke Of York’s manager John Barrenechea said: “It’s almost 100 years old and needs a complete overhaul because it has stopped working.”

But historic clock restoration is a fading skill in this country and finding specialists has proved difficult.

Mr Barrenechea said: “For a while we thought we’d have to use Italian clock workers but eventually we found Public Clocks Limited in Slough, which was as local as we could get.”

The task at hand is no small one – they will need to dismantle the clock and take it back, piece by piece, to their workshop.

They will then have to strip it down, clean it and examine the gearing, weight lines, pulleys and pivots.

Finally, they will return, refit and synchronise it.

The job is expected to cost more than £2,000.

Quirky But staff say the clock is not only an essential part of the cinema but also a quirky part of their job.

Over the decades, employees have been surprised to find “swinging the clock” on their job description.

Every week they have to swing a pulley inside the cinema to keep the hands turning for the next seven days.

But recently, “the swing” has only kept it going for a couple of hours.

Mr Barrenechea said: “The swinging of the pulley is part of the character of the place.

“It remains to be seen whether we will still need to do it when the restored clock comes back.”

To raise funds for the repair job, the cinema is hosting a special screening of the digitally restored version of Casablanca on September 22 at 9pm.

For more information, go to www.picturehouses.co.uk.

● The Duke Of York’s is the country’s oldest operating cinema.

● It was opened on September 22, 1910, with a showing of George Albert Smith’s Byways Of Byron. Mr Smith was a local film-maker who had a studio in St Ann’s Well Gardens in Hove.

● The cinema was constructed on the site of an Amber Ale Brewery and the original malthouse wall is still the north wall of the auditorium.

● The clock tower has been the centrepiece of the Baroque-style art house since it was opened.