Haldanes has officially commenced legal action against The Co-operative Group over allegations the society "materially" breached terms of its agreement when it sold 26 former Somerfield stores to Haldanes in late 2009.

"Proceedings were issued in the High Court on 10 May 2011 and served on The Co-op, through their lawyers, Clifford Chance, on 13 May 2011," confirmed law firm Nabarro, which is acting for Haldanes. "A formal pre-action letter setting out in full the basis of Haldanes' claims was sent to The Co-op on 23 March."

The news comes after Haldanes chairman, Arthur Harris, this week stepped up his attack on the society by claiming other retailers had also had issues with Somerfield stores they had bought from The Co-op.

"A number of well-known and well-respected retailers who purchased other stores from the divestment programme have suffered similar problems and in quite a number of cases had to close those stores down. We are in contact with and have the support of a number of those retailers," he said.

The Co-op continues to dispute Harris' claim he has been "sold down the river" and started its own legal proceedings against Haldanes in April in a bid to recover unpaid rent.