Travel firm Thomas Cook said it would cut 2,500 jobs from its UK workforce and close 195 stores in Britain as part of its plans to restructure the business.
The 172-year-old group has struggled over the last two years with a slump in sales leading to a string of profit warnings.
This has forced it to renegotiate bank loans and make disposals to cut debt.
Most of the job losses would be within its retail network and in back-office and administrative positions.
It would involve the closure of 195 of its 1,069 UK stores, said the world's oldest travel group, which has a total workforce of 15,500 in the UK and Ireland.
Thomas Cook said jobs at its head offices at Peterborough and Preston were at risk, while its Accrington office would likely be shut. It also plans to change the terms and conditions of some employees to cut more costs.
"We firmly believe these proposals will mean a better, more profitable, Thomas Cook that continues to be a major employer in the UK," the company said.
Travel firms and airlines across Europe have seen bookings fall over the last two years, hit by the euro zone debt crisis, high fuel costs and social and political unrest in popular destinations such as Greece, Egypt, Tunisia and Morocco.
Thomas Cook has been hit particularly hard by tough trading conditions in Britain where its core customer base of families with young children has been affected by the economic downturn.
Since travel industry outsider Harriet Green took over as chief executive last May, the company has seen a steady improvement in its finances after a series of disposals to cut its debt, including the sale of its Indian business and several Spanish hotels.
Earlier this week Thomas Cook said it had decided not to sell its under-performing French business and would instead kick off a restructuring programme to turn the unit around.
Thomas Cook last month reported reduced first-quarter operating losses and said its turnaround plan was on track.
Last year, the company had sought 23 redundancies from its 73-strong Irish workforce, based in Dublin. It shut its remaining stores in Ireland in 2009 and now operates in Ireland under a number of brands including Panorama and Sunworld, which are marketed through travel agencies, and online.