LONDON - British Prime Minister David Cameron on Tuesday formally launched his bid to renegotiate Britain's membership in the European Union, setting out his four key demands for EU reform.

Cameron has written to Donald Tusk, president of the European Council, to tell him his demands.

Cameron is also scheduled to deliver a major speech Tuesday to urge the EU to meet his demands ahead of an "in or out" referendum on Britain's membership in the EU.

In the speech, Cameron is expected to stress his four demands: protecting the single market for Britain and others outside the eurozone, exempting Britain from "ever-closer union" and bolstering national parliaments, limiting EU migrants' benefits in Britain, and enhancing competitiveness in the EU.

On Monday, Cameron said that he had "no emotional attachment" to the EU institutions and wanted to "debunk" the idea Britain could not survive outside the EU.

Addressing a national business conference, he said he was not satisfied with the status quo and Britain had to renegotiate its deal with Europe.

If he got the changes he wanted, Cameron said, he would campaign "vigorously" to stay in the EU; if not, he would "rule nothing out."

Cameron has pledged to hold a referendum on whether Britain should withdraw from the EU by 2017.(Xinhua)