By Jess Sharp, Money team

We first came across Tom McPhail when he posted this on X… 

The pensions expert appeared to be suggesting state pensions were at risk of disappearing.  

After speaking to him on the phone, he confirmed that was exactly his concern, warning something needed to be done sooner rather than later to avoid a “catastrophic” situation.  

He described state pensions as a social contract – each generation pays taxes and national insurance, which funds the pensions of today’s older people, and they hope the following generation will do the same for them.

But with population growth slowing, there’s a worry there may simply not be enough people to keep the system afloat in the future.  

“There’s a significant demographic shift going on in the UK. It started before the Second World War, cohorts of people born in the 1930s have been experiencing significantly longer lives than was the case prior to that, so people now in their 80s are living quite a lot longer,” he said. 

“But at the same time, we’ve got fewer children coming through. And so this exacerbates the shift in the age of the population.”

He said if he was 20 today, he would be “sceptical” about the promise of a state pension because he isn’t sure how it’s going to be paid for.  

At the moment, the state pension system costs around £120bn a year and more than half of retired people rely on it to make up at least 50% of their income, he added.  

Over the next 50 years, Tom predicts the proportion of GDP the state spends on older people will increase from around 16% to 25%.  

“I hesitate to use the word unsustainable, but it will certainly start to look challenging,” he said.  

“If we suddenly switched off the state pension or significantly reduced it, people would be in trouble, so the government can’t do that. 

“You can’t keep on progressively ratcheting up a more and more generous state pension. The costs of state pensions is going to become increasingly difficult for the younger cohorts to bear.”

He pointed to a few ways to potentially salvage the state pension – policy change, more babies being born or people working until they are in their 70s.  

“Politicians are going to have to make decisions about how to get out of this kind of political bind,” Tom added. 

“Time and time again it’s just kick the can down the road on the pension question, just put a sticking plaster on it and let the next government deal with the problem. 

“You can’t keep doing that. So I would really like to see, on the other side of this forthcoming general election… whoever’s in power, in collaboration with whoever’s in opposition, to just really open it up to some honest conversations about where the demographics are going to take us.” 

He does note there is one piece of good news: “This happens quite slowly, so we do have time on our side.”