The PM opened the session by announcing an “uncompromising” crackdown on benefit fraud which will be unveiled in the autumn.
Mr Cameron said that welfare and tax credit fraud and error creates a cost to the taxpayer of £5.2 billion a year - the equivalent of more than 200 secondary schools or more than 150,000 nurses.
He said a simplified benefits system being developed by Work and Pensions Secretary Iain Duncan Smith would help reduce the £1.6 billion annual bill for administrative errors.
The PM said:
There are some people who are claiming welfare who are not entitled to it and that is just wrong and that should stop.
As a country as we start to make savings to get our budget deficit under control the first cut we ought to make is the welfare payments to people who are not entitled to it.
Other topics under discussion in Manchester included poverty, drug abuse, Turkey joining the EU, discipline in schools, asylum seeker children, dentistry and the construction industry.