Former work and pensions secretary Stephen Crabb has joined the growing calls for the government to drop its policy to uprate state pension payments.
Under plans first introduced under the Tory Lib Dem coalition, the government currently links payments to average earnings, the consumer price index or 2.5 per cent, with payments increasing by whichever is greatest.
However, there have been growing questions over the validity of the so-called "triple lock", and now Crabb - a candidate to lead the Tories during the summer - has warned it has "served its purpose".
"I think there will be a case after 2020 to look again at that, to see if we can't rebalance our welfare spending to ensure that more goes to working families," Crabb told BBC Radio 4's Westminster Hour last night.
His comments mean that both of the previous work and pensions secretaries have now come out against the "triple lock" - Iain Duncan Smith also criticised the policy at the time of his resignation early in the spring.
And parliament's pensions watchdog has also called for it to be scrapped, meaning that pressure is now growing on the government from all sides.
The 2015 election manifesto committed the Conservatives to maintaining the "triple lock" until the end of this parliament, rather than a specific date.