An opinion poll for the Sun has found more people thought none the worse of Gordon Brown for describing a Labour voter as a "bigoted woman", than believed he was a hypocrite – but the newspaper decided not to publish the figures.

The results provide some comfort for Labour after the incident continued to dominate the news agenda for much of the day, overshadowing the build-up to the final leaders' debate. They also indicate that the embarrassing episode for the prime minister has had a minimal effect on voter intentions.

Voters were asked about their perception of the Labour leader in the aftermath of the insulting private comments he made about 65-year-old Gillian Duffy, caught on an open Sky microphone yesterday, after she had challenged him on issues including the national debt and immigration. The prime minister later apologised to Duffy in person for his comments, saying he was a "penitent sinner".

Asked if they agreed with the statement "It's a storm in a teacup. Mr Brown was simply trying to let off steam in private. We should not think the worse of him", 50% of those polled by YouGov agreed.

By way of comparison, 46% agreed with the statement: "Mr Brown is a hypocrite – saying one thing in public and the opposite in private." The remaining 4% of respondents were undecided.

The survey, carried out yesterday, also showed that just 9% of the 527 people polled said the episode was less likely to make them vote Labour, while 3% said it was more likely to make them vote Labour. The overwhelming majority – 83% – said it would not affect their voting intentions.

The Sun's failure to run the results is likely to be seized upon by critics of the paper who have accused it of not publishing the details of polls that are unfavourable to the Conservatives. The Sun announced it was backing the Tories, after 12 years of support for Labour, in September last year. Last week the Lib Dems accused the paper of suppressing the results of a YouGov poll that showed that if people thought Nick Clegg's party had a significant chance of winning the election, it would win 49% of the votes, with the Tories winning 25% and Labour just 19%.

The Sun also decided not to publish the details of another poll taken yesterday that was favourable to the Lib Dems. It showed that 29% of people thought the Lib Dems were being the most honest about spending cuts, compared to 26% who named the Conservatives and 21% who plumped for Labour.

The Sun's decision not to run the "bigot-gate" poll was highlighted by Mark Pack, co-editor of the Liberal Democrat Voice website. He noted the results had appeared on the YouGov website – in compliance with the rules of the British Polling Council. There is no question YouGov had done anything wrong. Pack added: "The Sun do commission more opinion polls than you would expect them to publish ... but it's very striking when you have the Sun running a story and they have put forward a polling question that gives a very different slant [in its results]."

The Sun had not responded to the Guardian's request for a comment by the time of publication.