British police said yesterday they would investigate the expense claims of some members of Parliament in a scandal that has tarnished the image of Britain's three main political parties.

Voters have been angered by weeks of disclosures about claims for everything from floating duck houses and cleaning a moat to mortgages that had already been paid off, at a time when ordinary people are having to scrimp.

The investigation will cover a small number of MPs and peers in the upper chamber, the House of Lords, London's Metropolitan Police said in a statement.

A police and Crown Prosecution Service panel will continue to consider a small number of other individuals, it added.

"After consideration by the joint Metropolitan Police and Crown Prosecution Service assessment panel the Met has decided to launch an investigation into the alleged misuse of expenses by a small number of MPs and peers," the statement said.

Police would not say who was under investigation, or which party they belonged to.

The scandal has ended the careers of more than a dozen MPs who have said they will not stand at the next general election.

Prime Minister Gordon Brown's government has been battered by the expenses row and the worst recession since World War II.

The opposition Conservatives are tipped to win a general election due within a year but analysts say voters could switch to supporting fringe parties or independents, potentially crimping their majority.

Individual MPs have paid back thousands of pounds after they were found to have abused the system in a variety of ways.