The Government is launching an advertising campaign targeted at nearly 50 towns and cities to urge claimants to report changes in their circumstances or risk a jail sentence.

Ministers are highlighting the types of fraud that are hiking up the estimated £1.1 billion benefit fraud bill, such as people who fail to say a partner has moved in or who don't notify the authorities if there is more money coming in.

The campaign also appeals to members of the public to call the benefit fraud hotline if they suspect someone is claiming benefits illegally.

Calls to the hotline topped 150,000 in the last year, an average of more than 600 calls every working day.

Department for Work and Pensions Minister Mark Harper said: "We are giving benefit claimants every opportunity to tell us if their circumstances have changed, as the majority do. But those who cheat the system need to know we will use everything in our power to stop them stealing money from hardworking taxpayers, and that they could land themselves in jail when they're caught.

"Our fraud investigators have new and better methods of detecting benefit cheats so it's becoming harder to hide and more difficult to escape punishment."

Area fraud investigator Jane Baker said: "What might seem like a white lie can quickly escalate into a serious case of fraud, with the claimant suddenly finding themselves owing thousands of pounds to the taxpayer and risking a prison sentence."