Two Labour former culture ministers have accused George Osborne of “seriously unacceptable” political interference in the BBC before the general election and next year’s licence fee negotiations, after the chancellor attacked its reporting about future public spending cuts.

Ben Bradshaw, the former culture secretary, said Osborne was trying to scare the BBC and warned it was part of a wider drive by Conservatives to intimidate the public broadcaster before voters go to the polls next May.

The MP, who is a member of the House of Commons culture, media and sport committee said the BBC needed to stand firm against such accusations of bias because the level of political aggression directed against the public service broadcaster ahead of the election was “going to get worse”.

He also accused the government of delaying negotiations over the BBC’s charter renewal until after the election in order to “hold the threat of abolishing the licence fee or dismembering the BBC over its head in an attempt to cow them between now and the general election”.

David Lammy, another former culture minister, who is now planning to run to be Labour’s candidate for London mayor, also said it was “seriously inappropriate for senior members of the government to be launching a scathing attack on a neutral media organisation over which they have financial power”.

“This reeks of subtle intimidation and we should be asking serious questions about the way in which George Osborne is trying to influence how the state broadcaster covers his policies, given that he is the man pulling the BBC’s purse strings,” he said.

The row originally broke out early on Thursday morning after Norman Smith, the BBC’s associate political editor, made a reference to George Orwell’s Road to Wigan Pier, a book about the depression-era 1930s, as the Office for Budget Responsibility stated that cuts set out in Treasury assumptions would see the state reduced to its smallest size relative to GDP for 80 years.

In an interview shortly afterwards on BBC Radio 4’s Today programme, Osborne accused the BBC of allowing “totally hyperbolic” reporting about his spending plans and conjuring up bogus images of the 1930s slump. At least two Conservative MPs then made a link between perceptions about the BBC’s neutrality and its charter renewal which is due to be negotiated after the election.

The row was gleefully seized upon by the rightwing media with the Daily Telegraph leading with “Tories at war with ‘biased BBC’” and the Daily Mail putting “Tories go to war with BBC over cuts” – capping a week of hostile reporting on a scale not seen since the Savile crisis.

But the BBC, often criticised for struggling to defend itself in a crisis, held its ground and defended Smith, with one source inside the broadcaster saying: “We work incredibly hard to ensure our reporting is fair and balanced. The truth is that the BBC is criticised from all sides – one day we’re accused of being a government mouthpiece, the next we’re attacked by ministers.”

The corporation had also hit back against a report and editorials in the Sun earlier in the week, which accused it of employing too many executives on salaries exceeding that of the prime minister and failing to provide value for money.

Unusually, the BBC issued a point-by-point rebuttal, annotating the Sun’s editorials, and writing on the corporation’s website that the licence fee was value for money at £2.80 per week and remained the most popular model for funding the broadcaster.

But such are the suspicions in Labour ranks that one shadow minister even suggested the BBC had already been cowed by the attack enough to lead its bulletins on the British Museum’s decision to loan the Parthenon marbles to a Russian gallery instead of persisting with a top news story about the autumn statement and public spending.

However, there were also signs that Downing Street was trying to de-escalate the controversy. David Cameron’s official spokesman said the prime minister completely agreed with the chancellor’s complaint, but only took issue with the particular reports about the autumn statement and was not accusing the broadcaster of systematic bias.

The issue of the licence fee is likely to become even more politically sensitive during the election because the Tory right and Ukip leader Nigel Farage are together pushing for it to be reduced.

On Friday, Farage told LBC 97.3 radio that the licence fee would “take a great big hammering under Ukip”.

He said: “I’m happy to have a small amount for the licence fee to keep that original public service broadcast remit to inform and entertain. That’s what it’s there to do and I think it’s just grown like Topsy. And did I see this week that there were 140 people working for the BBC who earn more than the prime minister. Sorry, something’s got to give. You know something’s got to give.”