Image caption Deborah Mattinson says she feels voters' opinions were not taken into consideration

A former Labour pollster has told the BBC that a report into why Labour lost the 2015 election is a "whitewash and a massive missed opportunity".

Deborah Mattinson completed voter research to feed into Dame Margaret Beckett's report, but says her evidence was not published.

Ms Mattinson told BBC Sunday Politics she was "very concerned" that lessons from the election would not be learned.

Labour said the Beckett report had "consulted far and wide".

Ms Mattinson, whose research was conducted in marginal constituencies in places including Croydon, Watford, Nuneaton and Glasgow, insists she had briefed Dame Margaret before the release of her report.

"I was somewhat disappointed not to see some of that reflected back," she said. "Yes, she picked up on the economy, but there actually was no analysis. It's reduced down to one bullet point in the report."

Ms Mattinson said voters "didn't trust Labour to manage the economy" and they "categorically" blamed the party for the 2008 financial crisis.

She also said people did not see Labour leader Ed Miliband as "prime ministerial".

"If you look at every election since the '70s, what you see is that the party that has the leader with the best ratings is the party that wins. There's no exception to that," she added.

No 'divine right'

She said the report was "quite apologetic, lots of defensive stuff in there - but nothing that really shone a light on what had gone wrong".

"I feel very concerned that these lessons won't be learned," she said.

"I can't see how they will be learned, because [the report] was the vehicle, that was the moment - and if this report didn't address those issues then I am not sure when they will be addressed."

She added: "No political party has a divine right to exist and unless Labour really listens to those people it must persuade, it stands no chance of winning the next election."

Image copyright PA Image caption The report said there was a perception that Ed Miliband was not as strong a leader as David Cameron

The report did say that Labour faced a "huge challenge" to win again in 2020.

Overseen by Dame Margaret, a former Labour foreign secretary and acting party leader, it summarised four main reasons for Labour's defeat, indicating:

Mr Miliband was not judged to be as strong a leader as David Cameron

A failure to shake off "the myth" that Labour was responsible for the financial crash and a failure to build trust on the economy

An inability to deal with the issues of "connection" and, in particular, failing to convince on benefits and immigration

The fear of the SNP "propping up" a minority Labour government

The report also said assumptions that Labour lost the election because it was too left-wing and because its policies were unpopular were overly simplistic and should be treated with caution, adding that the manifesto was an "impressive document."

Labour said the Beckett report had "consulted far and wide", taking input from pollsters, pundits and academics.