All 555 Thomas Cook shops are to be bought by rival Hays Travel in a move that could save up to 2,500 jobs.
The independent travel agent said the move gives it shops in areas where it had little or no presence, including Scotland and Wales.
John Hays, who set up the Sunderland-based firm 40 years ago, said he hoped the shops would reopen within days.
It had been an emotional day, he said, with many staff crying when they were told their jobs were saved.
He said it was difficult to give cast-iron guarantees about every Thomas Cook shop, because there would now be talks with individual landlords.
However, "it is certainly our intention to take on all the staff; to welcome them back," he added. The shops will be branded under the Hays name.
There is likely to be some overlap of stores, and the BBC estimates that there are more than 30 locations where there would be two competing High Street branches. In Yorkshire and the North East, for instance, there are branches just streets apart in Sunderland, Newcastle, York, Leeds, Doncaster, and at Morpeth, South Shields.
The acquisition, for an undisclosed sum, is a significant step for Hays, which has 190 shops, 1,900 staff, and last year had sales of £379m, reporting profits of £10m.
Mr Hays, who owns the business with wife Irene, said: "It is a game-changer for us, almost trebling the number of shops we have and doubling our workforce - and for the industry, which will get to keep some of its most talented people."
'It's been emotional'
The takeover deal was struck with the travel industry regulator, the Civil Aviation Authority, after several days of negotiations. He said he was "elated to get the deal over the line. It's been emotional".
Many ex-Thomas Cook staff had cried when told they still had jobs, he said. "These people did nothing wrong. One day they were in jobs, and the next day they were locked out."
He expected many of the shops to reopen on Thursday, "although probably with a skeleton staff". There were some logistics problems - Hays had still to locate many of the shop keys, he said.
More than 100 new jobs will be based at the company's Sunderland headquarters, with the rest in shops across the UK. The company has tweeted, urging former Thomas Cook staff to apply.
When Thomas Cook collapsed, it put 22,000 jobs at risk worldwide, including 9,000 in the UK.
It also sparked the biggest ever peacetime repatriation by the Civil Aviation Authority (CAA) to bring more than 150,000 British holidaymakers back to the UK. The last flight to repatriate Thomas Cook customers landed at Manchester Airport on Monday.
Business Secretary Andrea Leadsom said she hoped the deal "will provide significant re-employment opportunities for former Thomas Cook employees, alongside the advice and support we will continue to provide to help people find a new job as quickly as possible".
Hearts in our mouths 🙏🙏🙏 - @BBCBusiness @collettasmith with these lovely ladies from #ThomasCook just as @HaysTravel call & confirm their store WILL REOPEN & they can get their jobs back. Tears all round - very lucky to be part of this happy moment— Rebecca Wearn (@RebeccaWearn) October 9, 2019
'We've not been told anything'
Samantha Kennedy, 34, from Alness in Scotland worked at an Inverness branch of Thomas Cook for six years.
She told the BBC that her WhatsApp chat group had been "going crazy this morning since the media started reporting" the deal.
"We've not been told anything. My manager hasn't been told anything. It would be absolutely amazing if it was true," she said.
Samantha said she was sad the Thomas Cook brand had gone, but she loved working in the industry.
"To continue to work in the industry would be amazing and there's not many travel shops in Inverness, so if Hays were to take over I think people would be pleased."
'Deal with landlords'
The Transport Salaried Staffs' Association (TSSA) union, which had members in Thomas Cook shops around the UK and in its head office in Peterborough, welcomed the move.
Manuel Cortes, TSSA's general secretary, said it offered "real hope of reemployment to former Thomas Cook retail staff, many of whom are our members."
The business is thought to have a licence for six months to occupy Thomas Cook stores, giving Hays time to strike new deals with landlords.
Ian Bell, head of travel and tourism at accountancy firm RSM, said it was a "shrewd move" for Hays, but would also represent a quadrupling of its travel agency stores at a time when customers are increasingly booking holidays online.
"Much may depend on the deals that Hays can strike with its new High Street landlords," said Mr Bell.
As Hays bought the stores from the administrators, it means it will have bought them at a lower price than if Thomas Cook was still trading.
Julie Palmer, partner at Begbies Traynor, said that in waiting, Hays had got a "best price" for the stores.
However, she questioned the logic for the transaction at a time when customers are turning away from High Street travel agents.
"You have to wonder what Hays' plan is and how they can make it a success.
"Has the travel firm been gung-ho in trying to secure a cheap deal without assessing the viability of taking on these stores?," she asked.
Hays Travel is not like Thomas Cook, which owned hotels and an airline. Pippa Jacks, group editor of Travel Trade Gazette, told the BBC: "They don't have a [large] tour operating arm, they don't have an airline, they don't own hotels or cruise ships… so it makes them quite nimble in terms of what they sell".
Hays is said to have beaten off other bidders, which she said suggested that the package holiday industry was not dead.
"If you're spending a lot of money, if you're not particularly confident and you want some personal recommendations, actually going to see a real human who will sit and listen and take time to understand your personal requirements is very valued by a lot of holidaymakers," she said.
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