According to a poll, at least half of voters doubt the major parties' ability to pay for the promises made in their manifestos.

All three political parties—the Conservatives, Labour, and Liberal Democrats—released their manifestos last week, claiming to have fully estimated the costs of their plans to make them affordable.

However, according to an Ipsos survey released on Tuesday, the majority of people do not hold that opinion.

Some 50% said they were not confident that Labour could afford the policies in its manifesto, with just 37% saying they were confident.

But the figures for the other main parties were worse. Just a quarter of voters were confident the Conservatives could afford their policies while 62% said they were not.

For the Lib Dems, 57% said they were not confident their policies were affordable.

Asked how the parties would respond to their policies proving unaffordable, more than half the public thought Labour would raise borrowing, increase taxes or not deliver on all their plans, while 67% thought the Conservatives would not deliver and 52% expected the Tories to cut spending.

Keiran Pedley, UK director of politics at Ipsos, said proposals to improve public services tended to poll best, even if the public were “sceptical that any party can deliver all they have promised within existing spending plans”.

The top-polling policy for each party related to the NHS, with 87% supporting the Lib Dems’ promise to guarantee patients can start cancer treatment within 62 days of an urgent referral – the highest polling of any policy.

Some 83% backed Labour’s pledge to deliver 40,000 new NHS appointments a week, while 74% supported Tory plans to increase NHS spending and build 100 new GP surgeries in England.

The least popular policies from each party were lowering the voting age to 16, included in both the Labour and Lib Dem manifestos and opposed by just under half of voters, and the Tory plan to reintroduce national service, which was opposed by 45% of people.

Overall, 63% of people said Labour’s manifesto would represent a positive change for Britain, compared with 55% who said the same about the Liberal Democrats and 44% who said the same about the Conservatives.

Mr Pedley said Labour would be “encouraged” by this finding, and “look to build on that relative goodwill – compared to others – as polling day approaches”.

Polling on the Liberal Democrat and Conservative manifestos surveyed 1,170 British adults between June 11 and 12. Polling on the Labour manifesto surveyed 1,083 British adults between June 12 and 13.