Rishi Sunak refused three times to commit to maintaining the pensions triple lock beyond the next election, as Keir Starmer mocked him as “inaction man” over national security. In his final Commons grilling before MPs break up for party conference recess, the prime minister was evasive about the future of a policy that has become a hallmark of recent Conservative governments. After the work and pensions secretary, Mel Stride, hinted the long-term sustainability of the triple lock was in doubt, Sunak said only that the Tories had “always stood up for our pensioners”. About 12 million pensioners would be affected by any potential changes to the triple lock, which guarantees that pensions increase in line with average earnings, inflation or 2.5%, whichever is highest. The SNP’s Westminster leader, Stephen Flynn, twice pressed Sunak to confirm the policy would be included in the next Tory election manifesto. However, the prime minister declined to do so. Instead, he pointed to a £3,000 increase to the state pension since 2010, and claimed there were 200,000 fewer pensioners living in poverty in the same timeframe. “This is the government that introduced and is committed to the triple lock,” he added. The phrasing echoes similar wording from No 10 in recent days. Downing Street has been keen to stress the government remains committed to the triple lock as it is still official policy but refused to be drawn on whether it will remain so after 2024. Asked a third time by Ashley Dalton, a Labour MP, whether the triple lock could be ditched, Sunak repeated his assurance that he was still committed to it. The Guardian revealed this week that Treasury officials were discussing a one-off break from the pensions triple lock. The move could save £1bn by preventing an 8.5% increase next year. Starmer avoided raising the issue, after Labour’s deputy leader, Angela Rayner, refused to commit her party to maintaining the triple lock after the next election. After PMQs, Downing Street said Stride had been talking about the “very, very long term” feasibility of the triple lock when he cast doubt on its future, and the government was still committed to it in the “long-term”. Sunak’s press secretary stressed there was a statutory process already in place for deciding on the coming year’s pension rise. A Labour spokesperson said that given it was the Conservatives who put it in their 2019 manifesto, “the responsibility is on them to maintain the promises that they made at the last election”. Starmer focused his attacks at PMQs on Sunak’s handling of national security issues – describing him as “inaction man”. Starmer said the government had failed to heed warnings about HMP Wandsworth, where a terrorism suspect recently escaped, and not standing up to China after accusations two Tory MPs employed a spy working for Beijing. “Probation, prisons, schools, China: yet again inaction man fails to heed the warnings and then blames everyone else for the consequences,” said Starmer. He also said 40,000 migrants had arrived by small boats in the year Suella Braverman had been home secretary – although he added, to laughter: “That is if you overlook the six days she missed when she was deemed a national security risk.” In retaliation, Sunak said Starmer had shown a “principles-free, conviction-free type of leadership”. He added of the Labour leader: “The British public can’t trust a word he says.”