Calls for the creation of an ombudsman to protect homeowners from sub-standard new houses are intensifying after concerns emerged over the independence of the biggest warranty provider.

Oliver Colvile, the Conservative MP who chairs an all-party parliamentary group for new builds, said that he was seeking a meeting with Gavin Barwell, housing minister, to promote the idea.

His intervention came as it emerged that the National House Building Council, which provides warranties for new homes, pays millions of pounds a year to builders.

The existence of such payments has renewed concern over the impartiality of the NHBC, which provides warranties and insurance for more than 1.6 million homes, representing about 80 per cent of the warranties market.

A spokesman for the NHBC, a non-profit organisation…