Councils should use their new public health role to fight obesity and help cut the weighty £5.1bn annual NHS bill spent tackling the issue, a flagship London council and local government experts are poised to report.

A report to be issued next week by Westminster City Council and the Local Government Information Unit (LGiU) think tank, urges councils to use smart cards to incentivise and monitor residents in receipt of council tax benefit and housing benefit to improve their health. 'Where an exercise package is prescribed to a resident, houisng and council tax benefit payments could be varied to reward or incentivise residents,' it says.