Businesses are expected to learn on Monday how the Treasury will offer continued, but reduced support with energy bills.

Chancellor Jeremy Hunt is due to outline his plan to MPs as they return to the Commons and will repeat his message to business groups last week that the existing scheme, expiring at the end of March, is “unsustainably expensive”.

Westminster sources have said the replacement programme will provide a discount on wholesale prices, not a fixed price. Heavy users of energy will receive a larger discount.

Mr Hunt last week told business leaders that the current scheme is costing £18bn and reiterated it was always planned to operate for six months.

The energy support scheme is mainly targeted at businesses, but is also for charities, and public sector organisations such as schools and hospitals.

Business groups have warned of a “cliff-edge” when the current support stops and in order to avoid this the new scheme is expected to run for a further 12 months.