Why were U.K. bill payers saddled with an extra £29Billion for their gas and electric?

On the 9th of May 2024 the CEO of Centrica was asked to explain why U.K. bill payers were saddled with an extra £29Billion for their gas and electric, driving many into hardship at the same time as Oil and Gas companies were making £65billion in profit. And why his company who made £3.3Billion profit felt they had to fire and rehire workers on worse terms and conditions.