Scrapping plans to increase fuel duty by 3p a litre could cost the treasury up to �1.5bn, it is claimed.

Norwich North MP Chloe Smith was asked to tell parliament what assessments the treasury had made about the proposed change, due to come into force from August, on jobs and vehicle use.

Nadine Dorries MP also asked what the estimated cost of not proceeding with the policy would be.

Miss Smith, economic secretary to the treasury, replied yesterday: 'Office of Budget Responsibility (OBR) certified forecasts of the fiscal impacts of government policy decisions are presented at budget and autumn statement.

'The OBR reported in September 2010 that changing fuel duty by one pence a litre has an effect on the public finances of around �500 million.'