Tom Stainer, the chief executive of the Campaign for Real Ale (Camra) group, said the cost of a pint would have to rise to “ridiculous” amounts to match the increase in running costs that pub landlords now face.
He said some pubs were seeing bills go up by 500 per cent to 600 per cent.
Mr Stainer said a Camra survey this summer found more than 50 per cent of the British public think the cost of a pint is already unaffordable, meaning customers would be put off by a £15 or £20 pint.
“What you can say with surety is you can’t possibly pass on these energy increases and you can’t increase the pint by 500 per cent,” he told a national newspaper.
“It just isn’t viable for pubs to pass [price hikes this big] on to consumers because people wouldn’t come drink at pubs anyway.”
He said: “So thousands [of pubs] could be affected by this. And they can close – and the difference with [pubs compared to] other sorts of businesses is once a pub closes it very rarely comes back.”
Mr Stainer called on the UK Government to take action and support the hospitality industry by reviewing energy costs, business rates and beer tax.
His warning follows craft brewer BrewDog’s announcement it would close six pubs, including three in Scotland, over its rocketing energy bills as it criticised the Government for being “clueless”.
Bosses of six of the UK’s biggest pub and brewing companies, including Greene King, Carlsberg Marston’s and Drake & Morgan, also signed an open letter to the Government, urging it to act to avoid “real and serious irreversible” damage to the sector.
The warnings come as it was suggested Liz Truss’s premiership will be framed by how she tackles the cost-of-living crisis.
Ms Truss, who will take over as prime minister on Tuesday, has campaigned on a promise to cut taxes.
After her Conservative leadership win was announced, finance experts suggested some other potential options that may be considered.
A package of cost-of-living support measures, including a £400 energy bill discount for households plus targeted support, was previously announced by Rishi Sunak – a rival of Ms Truss in the Conservative leadership race, when he was chancellor.
But in recent months some economic indicators have become more grim.
The Bank of England has warned inflation is set to soar to more than 13 per cent and average annual energy bills are set to jump by 80 per cent in October from £1,971 to £3,549.
Industrial unrest has also been mounting.
Citizens Advice says it is helping more than two people every minute typically with crisis support during the working day.
Andrew Goodwin, chief UK economist at Oxford Economics, said: “Liz Truss’s term as UK prime minister will be defined by her response to the cost-of-living crisis.”
He said he expected Ms Truss to “quickly pivot towards making large direct payments to households”.
Mr Goodwin continued: “Tax cuts provide support more gradually than fiscal transfers would, and households’ need is urgent given they face very large increases in their bills in October, January, and potentially April as well.”
Tom Selby, head of retirement policy at AJ Bell said tax cuts would “do little for those on the lowest incomes who most need support”.