The survey of 2,000 adults by CAMRA discovered that only a quarter of people though that prices were right in boozers across the country - and 56 per cent thought they were too high.
It revealed the average cost of a pint in London was now £5.20 - but could exceed £6 in some places. Across the UK it was £3.50, which was leading many to drink at home with beer bought in the off-trade, according to CAMRA.
Outside of London, beer cost £4.57 in Oxford and £4.35 in Edinburgh, while a pint was slightly cheaper at £4.24 in Brighton. The cheapest pint was in Carlisle - £2.35 - which is two-thirds of the UK average price.
But when compared to beer available in the off-trade, the figures are stark, with the cost being at around £1.50 for a 330ml bottle of craft or premium beer, and less than a £1 for large-volume lager and ale.
The study was done ahead of CAMRA's Great British Beer Festival in London, which kicks off tomorrow - and ahead of the November budget, where it is expected beer duty could rise by 2p per pint. Also, small pubs are due to lose their £1,000 rates relief by 2019, unless government takes further action.
National chairman of the group, Jackie Parker, said: "It's no surprise that most people are finding pub pints unaffordable, given the tax burden they're facing. Beer drinkers will naturally look to more cost-effective ways to enjoy a drink, such as buying from off-licences and supermarkets for home consumption.
"The result is incredibly detrimental to our local communities and to our own personal connectivity. Having a good local makes people happier, better-connected and more trusting. Furthermore, pubs help bring communities together and support the local economy.
"The reality is that there are very few places that can replicate the benefit provided by our nation's pubs, and once they're gone, they're gone for ever."