According to the National Housing Federation, 1.5m low-income households pay £40 a year more for energy than those paying quarterly.

A new bill – The Equalisation of Tariffs for Gas and Electricity – will be taken to the House of Commons today, which would make it unlawful for energy companies to discriminate against their poorest customers.

The National Housing Federation claims that energy companies profit by an extra £50 million a year, or £40 extra per household, because of the additional charge they impose on pre-pay customers – which typically come from low-income households.

If passed, the bill, which is being taken to the House of Commons by a group of cross-party MPs – including Lib Dem Shadow Chancellor Vince Cable – will outlaw tariffs which “rip off” low-income families who pay their fuel through prepayment meters.

The Federation says that in the last year several energy companies, including Scottish Power, Npower and E.ON, have removed the premium on both gas and electricity. However, a number of the ‘Big Six’, namely British Gas, EDF and Scottish & Southern Energy, still penalise customers who do not pay by quarterly or monthly direct debit.

The Federation is calling on these suppliers, and the government to end the unfairness.

David Orr, National Housing Federation’s Chief Executive, said: “The energy companies have shamelessly ripped off their poorest customers over many years and at last this group of MPs is taking a stand by proposing a bill which would outlaw this blatant discrimination between different customer types.

“Millions of low income families are already struggling to make ends meet during the recession. Hitting them with the very highest fuel tariffs in the market is simply not acceptable and must be outlawed.”