The environment secretary Hilary Benn has warned that controversial plans to expand Heathrow airport should be rejected unless measures are taken to dramatically cut noise and air pollution.

Mr Benn told The Sunday Times that Britain’s biggest airport already had a problem with air quality even before the construction of the proposed third runway.

Benn’s statements have sparked rumours of a cabinet rift over the expansion plans, which are supported by Prime Minister Gordon Brown.

But a senior source close to Mr Brown told the newspaper that although air quality was an issue the project would still get the go-ahead.