The Audit Commission has strongly criticised the Conservatives over its "cavalier use" of the organisation's research in its local election campaign.

"Each of the main parties could analyse our data and produce results in their favour," an Audit Commission official said.

"We are not happy with the language the Tories are using. They have not taken on board what we have said. It is cavalier use of Audit Commission information and certainly should not be attributed to the commission."

Labour accused Iain Duncan Smith of "losing the plot" and making disgraceful claims.