The prime minister’s plan to end the triple lock on pensions is a “bad idea”, First Minister John Swinney has said.

The policy ensures that state pensions increase annually in line with inflation, average wage growth, or 2.5% – whichever is highest.

However, at the Labour conference, Andy Burnham said that from April 2030 the annual earnings option would be dropped.

Burnham also hit back at Swinney’s claim that he would be the UK’s last prime minster, insisting he was “determined” to prove the SNP leader wrong.

Under Burnham’s plans, state pensions would rise in line with inflation or 2.5% from 2030. It was later suggested the rate could rise by more than this in some years to ensure it holds its value relative to earnings.