In a statement the company blamed a ‘perfect storm’ of falling trade and rising rents, food and staffing costs for its failure.
The £4m turnover chain, which ran four London sites and one in Birmingham, went in to administration on 5 February after KPMG failed to find a buyer for the restaurant business.
All the loss-making restaurants were closed immediately with 50 redundancies across the group.
Square Pie was founded by Martin Dewey in 2001 and grew to seven sites in 2015.
The group launched a round of equity investment in March 2017 to help fund the development of a new brand aimed at turning around its struggling profits, but it raised just £100,000 of its £1m target.
Last summer Square Pie's directors loaned the company money to launch the new Square & Co concept store, featuring an expanded menu of street food-style hot buns and grilled meats with salads and slaws, but it was unable to save the business.
“The collapse of the restaurant business was something we were desperate to avoid, and we were hopeful even as recently as last weekend that we could save the stores and the jobs, but unfortunately the backing didn’t materialise in the current leisure climate,” said Dewey.
“Together with my colleagues, we worked tirelessly for over 15 years to create a fantastic brand, and I am devastated that we couldn’t make the restaurants work in the current economy. Whilst the wholesale side of the business remained viable, in the end we ran out of money to put into the business to keep the outlets.”
Square Pie’s wholesale business is still trading and will continue to fulfil all its orders.
The group has been purchased by entrepreneur Oliver Wessely, who acquired a majority stake in new venture Beat Foods Ltd – which has rights to produce Square Pie products for grocery and wholesale.
The present management team has been retained as a condition of the sale.
Luke Morgan, a career food industry professional who joined Square Pie in October last year, will become managing director of Beat Foods, which will be headquartered in Nantwich, Cheshire.
Square Pie is the latest restaurant group to face difficulties this year. Both Byron and the Jamie Oliver Restaurant Group have shut sites as part of restructuring plans, while Prezzo is also facing possible closures.