TSSA general secretary Manuel Cortes said the union had sought clarity from Cook after the historic operator said in March it would look to shut another 21 stores, placing more than 300 jobs at risk.

This was compounded by Cook posting a £1.46 billion half-year loss earlier this month, which included a £1.1 billion write-down of assets relating to its 2007 merger with MyTravel.

The TSSA said it has been “speaking to the company” after expressing “serious concerns” about members’ jobs. Cook has shut more than 200 shops over the past three years.

The union said Cook had also told its representatives it was not planning “major changes” to its current operating model in “the short to medium term”.

“We of course welcome this commitment from Thomas Cook that they have no plans to leave our high streets,” said Cortes. “Our members and many customers will be delighted to hear this.

“I’m also pleased that the company seems to feel that for the foreseeable future the Thomas Cook business model is not under undue stress.

“However, we remain committed to fighting for our members jobs at Thomas Cook and will press the company about the detail of their plans – especially around the number of high street shops facing potential closure in the coming weeks and months.”

Peter Fankhauser, Thomas Cook chief executive, said: "The priority is that we are maximising what we can get out of our retail stores, and really being efficient.

"We have always said we review the retail footprint constantly and if a shop is falling below the line of profitability and has no chance to return to profitability then we see where we can transfer the customer into the next shop and we close the shop when the leases expires."

The TSSA’s missive comes after Cook confirmed to TTG earlier this week it had spoken to investors about its vision for the future of the company.

This followed reports in the consumer media Cook was considering pivoting to become an “online marketplace” for holidays. Cook has declined to comment.

The company’s share price, meanwhile, rallied to a high of 18p this week, fuelled by confirmation of a bid by German investment firm Triton for its Nordic operations and several bids for Cook’s airline.