Calls for reform of the pensions Triple Lock from the pensions community are building as Chancellor Rishi Sunak departed from his usual approach of defending the lock on BBC Radio 4 this week.

In a discussion on the Office for Budget Responsibility (OBR)’s recent forecasts and what it means for the pensions uprating mechanism, Mr Sunak stopped short of his former promise to keep the lock.

Instead he said that while the government policy was to maintain the lock he was unable to commit to it because they government does not yet know what the earnings numbers will be yet.

Instead, he said he will ensure “fairness” when making decisions about the future for both pensioners and taxpayers.

The OBR has warned that State Pension costs could increase by £3bn if average earnings see 8% growth this year as some experts expect.

Under the Triple Lock rules, the State Pension is increased annually by the highest of earnings growth, price inflation, or 2.5%.

A spike in earnings is expected to be up to 8% this year as the UK recovers from the economic impact of the Coronavirus pandemic and the government’s furlough scheme comes to an end.

Sarah Coles, personal finance analyst at Hargreaves Lansdown, said Mr Sunak has, “set the cat among the pigeons” in departing from his usual line promising to preserve the pensions Triple Lock.

She said: “The reference to fairness to taxpayers and pensioners, and highlighting concerns about costs, was the Chancellor waving bolt cutters around the Triple Lock – either to signal a break away from the policy or to gauge the reaction.

“The crisis has thrown up an inherent problem with the mechanisms behind the triple lock, because it’s unable to cope with sudden and spikey wage changes. Sunak could address this by adding an element of smoothing of wage figures, so the spikes are evened out to a more gradual rise.

“However, he might also use this as an opportunity to revisit the Triple Lock, which is a massive cost for the government at a time when it’s watching every penny.”

There has been speculation that the government may look to scrap the third lock, so that pensions rise in line with the higher of wage increases or price inflation. However, the purpose of the 2.5% guarantee is to build in a gradual improvement to the State Pension which is currently one of the least generous State Pension schemes in OECD countries.

• Former Pensions Minister Baroness Ros Altmann has called on the government not to abandon the State Pension triple lock just because of one year’s figures.