UPDATE 1-British chef Jamie Oliver's restaurant chain to enter administration - source

British celebrity chef Jamie Oliver's restaurant chain will enter administration on Tuesday, a source familiar with the situation said, threatening jobs at the firm's 25 sites in the United Kingdom.

The source said that more than 1,000 jobs would be put at risk by the administration, a form of protection from creditors, which is expected to be announced later on Tuesday. Oliver founded his Jamie's Italian brand of a high street restaurant in 2008. His restaurant group also includes Barbecoa, a steakhouse, and Jamie Oliver's Diner.

Oliver is famed for his "Naked Chef" books and TV shows, which were broadcast in dozens of countries, as well as his campaigning over healthier school meals. Oliver's restaurant chain is the latest victim of a rough trading environment on Britain's high streets.

In March, Boparan Restaurant Group (BRG) said it planned to close more than a third of its Giraffe and Ed's Easy Diner outlets, while Carluccio's, Prezzo, Strada and Gourmet Burger Kitchen closed branches in 2018.