DAVID CAMERON has been less polite than Gordon Brown when responding to backbench MPs at Prime Minister's Questions, new university research claims.

The "Punch and Judy" politics Mr Cameron once vowed to end forms a major part of the sessions, the University of Manchester-published report adds.

Regarding impoliteness during Prime Minister's Questions, linguist James Murphy analysed three sessions from Mr Cameron's premiership and three from Mr Brown's as Labour leader.

The PhD researcher's approach included watching videos of six randomly chosen sessions and examining how phrases were uttered, such as whether an aggressive or condescending tone of voice was used.

A politeness theory was also used to assess how the MPs asked the questions and how the PMs responded during the weekly 30-minute sessions.

Mr Murphy said: "At PMQs, both Brown and Cameron are unfailingly polite when answering their own MPs. To do otherwise may indicate a rift within the party.

"In response to questions which are worded in a neutral way, Brown answers consistently politely. Cameron, in contrast, answers impolitely on around one-half of occasions.

"This suggests a mismatch between Brown's linguistic performance at PMQs and the public's perception of him."