The project is being overseen by PJ Livesey Group to restore the clock back to working order before the tower is transformed by converting the space into 22 properties.
The clock tower - often referred to as the “kitchen clock” by locals - is one of five Grade II-listed buildings that make up the purpose-built Terry’s factory estate.
The factory ceased production in 2005 and the buildings stood empty for a decade before being bought by a developer.
People will still have to wait before the clock starts working again as its mechanism is not due to be installed until the end of next year.
Between the site closing and PJ Livesey starting work the original mechanism – a rare Electric Turret Clock - disappeared. Smiths of Derby was commissioned to try to source identical parts from the same era.
Technical sales consultant Peter Sully said: “It has taken 18 months of detective work across the country but we managed to track down identical parts and are now in a position to make the mechanism.
“It has been a very demanding process but it will be very satisfying to see the clock working again.”
Among those looking on was former Terry’s electrician Peter Mortimer, 85, who said: “It’s an occasion really. It’s amazing how many people have missed that clock in the south bank area.”
Work to convert the space into new homes is expected to take 12 months, with the new apartments released for sale from next May.
The final part of the project will be the creation of a separate floor to the clock level space to allow public access on a set number of days each year.
Three boards, telling the story of Terry’s, the original clock manufacturers Gents and the PJ Livesey Project, will be displayed there.