The inquiry will examine whether Centrica-owned British Gas breached licence conditions relating to its obligations to domestic customers who switch to another supplier.

The inquiry comes after consumer affairs website Moneysaving Expert raised concerns about the issue, Ofgem said in a statement.

Ofgem licence conditions state that suppliers should not charge termination fees for any switch that takes place within the 49-day "switching period" before the expiry of a fixed-term contract, the regulator said.

(Reporting by Nina Chestney; editing by Jason Neely)