Construction giant Carillion has gone into liquidation, threatening thousands of jobs.
The move came after talks between the firm, its lenders and the government failed to reach a deal to save the UK’s second biggest construction company.
Carillion ran into trouble after losing money on big contracts and running up huge debts of around £1.5bn.
Its failure means the government will have to provide funding to maintain the public services run by Carillion.
“All employees should keep coming to work, you will continue to get paid. Staff that are engaged on public sector contracts still have important work to do,” said government minister David Lidington.
Carillion is involved in major projects such as the HS2 high-speed rail line, as well as managing schools and prisons.
It is the second biggest supplier of maintenance services to Network Rail, and it maintains 50,000 homes for the Ministry of Defence.
Defence Secretary Gavin Williamson told MPs there would be a meeting of the government’s Cobra emergency committee on Monday to discuss the situation.
Carillion chairman Philip Green said it was a “very sad day” for the company’s workers, suppliers and customers.
The company has 43,000 staff worldwide – 20,000 in the UK.
There are also thousands of small firms that carry out work on Carillion’s behalf. Many of those companies have expressed concerns about whether they will be paid.
One company, which provided services for Carillion’s prisons contract, said it might fail if it is not paid the £80,000 owed to it.
A worker on the Midland Metropolitan Hospital, who wanted to only be identified as Philip, said: “Everyone on the site got told: ‘That’s it, go home.’ My company said, ‘You’ve been laid off.’
“They’ve literally locked the gate. They’ve told us we can get our personal tools off the site if they’re small, but that’s it.”