Supermarket group Somerfield has been ordered to sell 12 stores after a study by the UK's competition watchdog.

The Competition Commission said it had taken the move to prevent a "substantial lessening" of competition in the local areas of the stores.

Originally, the Commission had voiced concerns over 14 of the 115 stores Somerfield bought from Morrisons in a £260m deal in 2004.

However, the Commission said the number had been reduced after consultations.

It added "new evidence" from Somerfield had eased concerns it had that the acquisitions of sites at Bedlington and Paisley would impact on the local grocery market.

"The findings will be considered by the Somerfield board at its next meeting on Thursday 8 September and a further announcement will be made shortly thereafter," Somerfield said in a statement.

Last month, the Bristol-based group attacked regulators for intervening in the deal.

In a submission to the Commission it accused the regulator of putting "the cart before the horse" when it made its provisional report into the takeovers.

It added the Commission had acted on a "theoretical possibility" that the group would act in a certain way after it had acquired the stores.

Following the ruling, Somerfield must now sell stores it bought from Morrisons in Filey, North Yorkshire; Middlesbrough Linthorpe; Newark; Pocklington, East Riding; Poole Bearwood; South Shields; and Whitburn in West Lothian.

However, in Johnstone, Renfrewshire, Peebles in the Scottish Borders and Yarm at Stockton-on-Tees the group can either sell its newly bought stores or close its existing outlet.

The Commission also ordered Somerfield to sell off stores it has already closed in Kelso and Littlehampton.