The loss of Marks and Spencer on Bridge Street will hit the city centre hard - unless a replacement store to fill the building is found soon.
The high street favourite announced it will be closing the branch early next year, with all staff and stock moved to the Queensgate branch.
Peterborough MP Stewart Jackson said: “Bridge Street is a very successful shopping street compared to others in similar sized cities.
“It is important we have another store come in soon.
“We said the same when Woolworths went bust, and TK Maxx came in - they have been a success.”
John Bridge, chairman of the Peterborough Chamber of Commerce, said there were ‘irons in the fire’.
He said: “We have been aware of the closure for some time. There has been an awful lot of work going on behind the scenes to ensure it doesn’t adversely affect that part of Peterborough.
“We are having confidential discussions with firms, and we are confident the store will not be empty for very long.
“It is important Marks and Spencer are committed to Peterborough, and they will have the revamped Queensgate store as well as the one at the Brotherhood centre.”
Works to improve the street scene in Bridge Street have only recently finished, and Peterborough City Council leader Cllr John Holdich said it was important to fill the vacated store space as quickly as possible.
He said: “It’s been the worst kept secret that the Bridge Street branch is not the most profitable.
“With the Brotherhood store opening, as well as Queensgate, there was never enough room for three Marks and Spencers branches in Peterborough.
“This move has been rumoured for a long period of time.
“There has been a lot of interest in the site, and I am sure we will fill the space very quickly.
“The city centre is doing well, and it is important to keep that going.”
The Queensgate store will undergo a major revamp over the autumn and winter to make space for the extra stock.
Store manager Emma Burrell said: “We are absolutely delighted with the news that we will be modernising our Peterborough Queensgate store.
“Not only will the new décor and layout conveniently bring our clothing and food offer under one roof, rather than split across two stores, but we are also delighted to introduce several new departments and a new 90-seat café.
“We are very excited by the changes, which will really enhance the customer shopping experience.
“This investment demonstrates M&S’s commitment to Peterborough and its customers, and we look forward to welcoming shoppers to the unveiling early next year.”
The Queensgate Marks and Spencers will remain open throughout the refurbishment works, but the Home and Kidswear departments, along with the Coffee Shop, will temporarily move to the M&S branch in Bridge Street in the autumn.