British Gas owner Centrica PLC (LON:CNA) has won an appeal against the energy regulator Ofgem over a last-minute change to price cap calculations that it said cost it £70mln at the start of the year.

The FTSE 100 firm requested a judicial review over a decision by Ofgem to change the dates within which wholesale energy prices are used to calculate the price cap.

READ: Centrica a “value wildcard”, says Jefferies as it ups to buy

Centrica said this last-minute change underestimated the cost of supplying energy over the last winter period, resulting in the higher one-off cost.

The company welcomed the judgement, saying it underlined “the importance of transparent and rigorous regulatory processes to ensure well-designed regulation that is in the interest of a well- functioning energy market”.

Centrica added that it will now work with the government and Ofgem to develop future energy policy for its customers.

In late-afternoon trading on Wednesday, Centrica’s shares were 2% lower at 73.3p.