John McDonnell will this weekend seek to draw a line under the bitter infighting that has gripped his party over the summer by kicking off an anti-austerity speaking tour in Conservative MP Anna Soubry’s Nottinghamshire constituency of Broxtowe.

The shadow chancellor, whose profile has increased significantly in recent months, plans to visit a constituency every few weeks until the next general election on what he is calling the “road to rebuilding the economy tour”.

Labour has struggled to get its message across in recent weeks, during the ongoing row over antisemitism, but McDonnell hopes to wrest the agenda back to the safer territory of rejecting Tory spending cuts.

“In Broxtowe and across the length and breadth of Britain, Labour will set out its plans to revive the economy and create jobs,” McDonnell said. Soubry, who has been critical of the prime minister’s Brexit stance, held Broxtowe with a majority of just 863 at last year’s general election.

As McDonnell’s nationwide tour begins, however, there is little sign of the two sides in Labour’s civil war being reconciled.

Chuka Umunna, the Streatham MP who was recently forced to deny that he was planning to leave Labour and set up a rival party, will give a speech in London on Saturday, urging the leadership to “call off the dogs” from MPs critical of Jeremy Corbyn, several of whom are facing motions of no confidence from their local parties.

He will say: “Having only been re-elected by their constituents last year, already centre-left MPs are being targeted systematically with motions against them for standing up for these values – for demanding we have a zero tolerance of racism in our party. More motions such as this are expected by colleagues.

“My message to our leadership: it is within your power to stop this, so call off the dogs and get on with what my constituency, one of the most diverse communities in the nation, demands we do without equivocation: fight this Tory Brexit. That is where all our efforts should be.”

Labour activists called for a party inquiry on Friday after an Iranian state-backed broadcaster streamed footage of the Enfield North MP, Joan Ryan, losing a confidence vote.

The Press TV footage, which appeared to have been filmed inside the meeting, was carried on the station’s Twitter feed and referred to Ryan, who chairs Labour Friends of Israel, as a “pro-Israel MP”. It included the hashtag #WeAreEnfieldNorth.

The local party chairman, Siddo Dwyer, said that filming was not allowed in the room and he would be making a formal complaint to the channel. “Warnings were issued about filming, including a direct warning to the member in question,” he wrote on Twitter. “It didn’t occur to any of us at the time that they were from a state broadcaster.”

But Roshan Salih, a journalist at Press TV, disputed that account. He told the Guardian: “No general warnings issued, no posters, no approach to person we obtained footage from.”

A Labour spokesperson said: “Filming of local Labour party meetings is not permitted and Enfield North will be reminded of this fact.”

Labour’s deputy leader, Tom Watson, said the filming made a farce of the proceedings and “is not how the modern Labour party should conduct its affairs”.

Ryan was critical of Corbyn over his stance on antisemitismduring the row that has preoccupied the party for much of the summer.

The no-confidence motion, which is not binding, accused Ryan of “smearing” the Labour leader’s character, “without him having the right to a fair and balanced defence”.

Another MP critical of Corbyn’s leadership, Gavin Shuker, who represents Luton South, was also the subject of a vote of no confidence from his constituency party on Thursday night, but he said he would continue to serve his constituents.

Labour’s unrest was further inflamed on Friday by remarks from the former prime minister Tony Blair, who said the party had “profoundly changed” under Corbyn’s leadership.

“It is a different type of Labour party. Can it be taken back? I don’t know,” he said on the BBC’s Political Thinking podcast.

The Momentum founder, Jon Lansman, a member of Labour’s national executive committee and staunch backer of Corbyn, shot back that Blair was “never in the right party and there will never be a return to his politics in Labour”.

Momentum is keen for grassroots party members to play more of a role in selecting and removing Labour’s candidates for parliament.