THE former boss of Marks and Spencer Lord Stuart Rose will head the campaign for Britain to stay in the European Union.

The Conservative was unveiled as chair of the In Campaign ahead of its official launch on Monday and said the UK was "stronger in Europe" and to leave the EU would be a "leap into the unknown".

The In Campaign said Lord Rose would take up the position with immediate effect.

Conservative, Labour and UKIP MPs have launched a cross-party campaign to take the UK out of the EU.

David Cameron has promised a referendum on the issue by the end of 2017.

Lord Rose said: “I believe that Britain is stronger in Europe.

“The choice in the coming referendum is between remaining stronger, safer and better off inside Europe, or taking a leap into the unknown, risking our prosperity, threatening our safety, and diminishing our influence in the world.

"“I believe the case for Britain to remain in the EU is clear. So I'm delighted to join the In Campaign's board as Chair, and I look forward to introducing the rest of the board at our campaign event on Monday."

Lord Rose spent seven years at M&S as chief executive and chairman and is expected to make the business case for Britain remaining in the EU. He is currently chairman of Ocado, FatFace and Oasis Dental Care.

Fellow Tory member of the House of Lords, former Chancellor Lord Lawson, is leading the Conservative campaign to leave the EU.

On Friday a cross party group of donors and politicians launched the “Vote Leave” campaign, while the rival “Leave EU”, backed by UKIP leader Nigel Farage, was unveiled last month.

A third campaign group, Business for Britain, is focusing on putting the economic case for leaving the EU.

The announcement about Lord Rose comes as David Cameron met with German Chancellor Angela Merkel to discuss his renegotiation strategy.