Ed Miliband’s leadership of the Labour party is under renewed pressure as sources close to Johann Lamont, who dramatically quit as Scottish leader on Saturday, claimed he banned her for a year from condemning the bedroom tax while he made his mind up on it.

The diktat from London over the policy, which forces council house tenants to pay extra for spare rooms, was said to be a huge frustration for Lamont who was to come under heavy personal attack for being vague over the critical issue. She accused colleagues of trying to run Scotland “like a branch office of London” on Saturday, when she announced her resignation.

Former Labour first minister Henry McLeish backed up Lamont’s accusation, claiming that the Westminster party did not have a clue about “the realities of Scottish politics” and faced a problem of “historic, epic proportions” that could cost it the next general election.

It is understood that Lamont was unhappy that the general secretary of Scottish Labour, Ian Price, was to be removed from office without her being consulted. Labour sources said that Price was called to London for “a chat” with the national party general secretary, Iain Mcnicol, earlier this month, where he was sacked on the grounds that he was working too closely with the Scottish leadership.

However, it is understood that there had been a number of other frustrations in dealing with Miliband, and his office staff, including the request that she avoid promises of a repeal of the bedroom tax, a stance which drew her heavy criticism throughout last year.

A source close to Lamont said: “They told Lamont not to condemn it for a year while Ed made up his mind.” In turn, a source close to Lamont said that Miliband was personally affronted when he was asked by Lamont’s office to play a more low-key role in the final stages of the referendum campaign that he had hoped.

They said: “The thing that got to Ed Miliband personally was when he wanted to be front and centre at the end of the campaign but we had to say: ‘you’re not well known here’. He didn’t want Gordon Brown to be the last image of the campaign – he wanted it to be him and was scraping around looking for a suitable event.”

A source close to Miliband denied that there had been any disagreement or upset caused and said that it was right for Scottish figures to be at the centre.

The fallout around Lamont’s resignation will however be hugely embarrassing for Miliband, and potentially damaging to Labour in Scotland. A spokesman for the Labour leader said that the process to elect a new Scottish leader would start in the next few days. It is understood that Miliband hopes to have the contest concluded within six weeks.

Michael Connarty, Labour MP for Linlithgow and East Falkirk, has backed former prime minister Gordon Brown to replace Lamont as “a towering figure” who was “speaking the language of the people of Scotland”. He told BBC Radio Scotland’s Good Morning Scotland programme: “We should be talking about Gordon and Gordon alone. I’ll be seeking him out and so will other people.”

Brown has not commented on Connarty’s call but issued a statement in which he said he was sorry to hear of the resignation of Lamont who, he said, “brought determination, compassion and a down-to-earth approach to the leadership”.

Lamont announced she was resigning as leader in an interview published in the Daily Record on Saturday in which she claimed “colleagues need to realise that the focus of Scottish politics is now Holyrood, not Westminster.

“Any leader whose general secretary can be removed by London without any consultation is in an untenable position. That has to change. The Scottish Labour Party should work as equal partners with the UK party, just as Scotland is an equal partner in the United Kingdom. Scotland has chosen home rule – not London rule.”

McLeish, one of Lamont’s predecessors as head of Labour in Scotland, said on Saturday: “I think Johann is absolutely right to make the comments she has made.”

He told BBC Radio 4’s Today programme: “For a decade now the party have been in decline and the SNP have been in the ascendancy. There has been a failure to rise to the devolution challenge. Overall though there has been a suffocating atmosphere of control that Westminster have been trying to put on Scotland. That’s what led Johann, I think, finally to leave.”

“Labour in Westminster, Labour in London has not a clue about the realities of Scottish politics. Johann has been badly advised. The influences on Ed Miliband have not been helpful. Now what we’ve got is a situation after a decade that Labour is still in denial in the UK and ... if there’s any hiccup in the number of MPs we send to Westminster in 2015 this could be catastrophic for Ed Miliband’s effort to become prime minister.”

The Glasgow Pollok MSP has represented her constituency since 1999, taking over as leader in December 2011 after the party’s bruising defeat by the SNP in the Scottish parliament elections that year. Her leadership was called into question during the referendum campaign, which proved a damaging experience for an already struggling party.

In her interview with the Daily Record, the paper reports that Lamont felt under particular pressure when a “senior colleague started lobbying members of the Scottish Labour executive to ask Lamont to go, while never doing so to her face”.

Despite Scotland voting to reject independence in September’s referendum, her position had only become more precarious, with suggestions that Labour could pay a high price in next year’s general election, significantly in the greater Glasgow area, where voters in 12 Labour constituencies backed independence.

But a source close to Lamont said this was a “fundamental misunderstanding of Scottish politics”. The source said: “Lots of people who vote for independence are Labour voters and will stay Labour voters.

“And there are more unionists who voted SNP in the last election than there are Labour supporters who voted for independence. There is an element of panic here. They are so desperate to get Ed Miliband in Downing Street that they have lost their way.”

Nicola Sturgeon, who will replace Alex Salmond as SNP leader and first minister next month, tweeted: “I wish Johann well … but if this is an accurate account of her reasons, @scottishlabour really is in meltdown”.