British foreign minister Liz Truss said on Sunday that she would set out immediate action in her first week in power to tackle rising energy bills and increase energy supplies if she is, as expected, appointed Prime Minister.

The governing Conservative Party is widely expected to name Truss its new leader, and Britain’s new Prime Minister, on Monday. Truss said she would be bold in tackling the flagging economy, repeating her pledge to spur growth to fix its long list of ills.

Writing in the Sunday Telegraph, she said she understood how challenging the cost-of-living crisis was for Britons and she would take “decisive action to ensure families and businesses can get through this winter and the next”.

“If elected, I plan within the first week of my new administration to set out our immediate action on energy bills and energy supply,” she said.

“A fiscal event would follow later this month… with a broader package of action on the economy.”

The Sunday Times cited insiders as saying the cost of Truss’s plan would easily exceed £100 billion.