The Institute for Fiscal Studies has said a government will at some point ‘have to move away’ from the triple lock because the policy is too expensive and unpredictable.
The thinktank estimates suggest that keeping the current system in place until 2050 could cost the government anywhere between £5bn and £40bn per year, with around £20bn per year considered the most likely outcome.
The problem is that the triple lock ties government spending to economic conditions that can change sharply.
READ NEXT: The triple lock risks bankrupting Britain
State pensions must rise by whichever is highest out of inflation, average wage growth or 2.5%, meaning sudden changes in prices or earnings can significantly increase the cost to the Treasury.
The current figures point towards another sizeable increase next year. Inflation is 2.9%, while average wage growth stands at 4.1%, so unless the latest earnings figures change the picture, pensioners are looking at an increase of roughly 4%.
That would add to a state pension bill expected to reach £154bn this year.
The IFS said: “While the triple lock has now been in place for more than 15 years, at some point a government will have to decide to move away from it towards a more predictable and less costly way of uprating the state pension over time.”
The state pension increase now hinges on one key figure
The next key figure will come on Tuesday, when the Office for National Statistics publishes its estimate of average earnings growth between May and July 2026. That number is expected to determine the increase under the triple lock.
The IFS said the policy has now been in place for 15 years, but argued that the government will eventually have to move towards a system that is cheaper and more predictable.
Prime Minister Andy Burnham has publicly backed the triple lock and said he will stick to the commitment made in Labour’s 2024 manifesto.
However, the latest warning suggests the pressure for reform is unlikely to disappear, even if the government chooses to keep the promise for now.