Jamie Oliver is to close three of his four Union Jacks restaurants, run in partnership with US pizza restaurateur Chris Bianco.
The news emerged over Twitter that the Chiswick, Winchester and Holborn branches were closing. The Covent Garden site remains open.
The tweet said: "It's no secret that the industry has been affected by the tough climate & a proposal has been made to close UJ Chiswick, Holborn & Winchester.
"We'd like to say a huge thank you to everyone, we have loved meeting you all. Please do pop along to our Covent Garden Piazza restaurant."
The three sites that are set to close have already been removed from the Union Jacks website.
It emerged in December last year that the Union Jacks chain could be sold or rebranded, having failed to perform as well as had been hoped.
Oliver launched brand, a British-influenced restaurant serving flatbread pizzas, in 2011 with Bianco.