M&S, the high street retailer, plans to close 27 shops after one of its worst Christmas trading periods.

It today said, following a store portfolio review, it would close 27 stores – 25 underperforming Simply Food stores and two small main chain stores.

It said around 780 jobs might be lost as a result of these closures with a further loss of up to 450 jobs, representing around 15% of its head office headcount.

It revealed for the 13 weeks to 27 December 2008 group sales were down 1.2%

Chairman Sir Stuart Rose said: 'Group sales were down 1.2%. Sales in the UK were down 3.4%. Our trading stance throughout the quarter enabled us to offer our customers great value, grow our volumes, maintain our leading market position and uphold our ethical stance. Our post Christmas sale which started on 27 December with 15% less stock into sale than last year has cleared quickly. We have made good progress on the key priorities set out at the interim results in November.’

It said its UK like for like sales were down 7.1% but online sales were up 29%.

It hopes its cost initiatives are set to reduce its underlying cost base by £175m to £200m.