JEREMY Corbyn has insisted he is not a bully after a senior Labour critic claimed the party leader had threatened to call his father to apply pressure on him to stop speaking out.

The Labour leader, accused of allowing a “culture of bullying” to grow under his leadership by his rival for the Labour crown Owen Smith, said he wanted his colleagues to concentrate on "political issues" amid claims that he had "contributed" to the abuse of his critics.

Mr Corbyn also faced accusations that he was "driving a wedge" between different parts of the Labour Party by raising the prospect of re-selection hearings for candidates at the general election. Many fear re-selection means de-selection of moderate MPs.

The party leader said he was "disappointed" by the claims and said: "I don't do any abuse, I don't do any bullying."

Mr Corbyn, who is fighting former shadow work and pensions secretary Owen Smith to hang on to the party's top job, is favourite to win the postal ballot of Labour's members - whose ranks he said have swelled to more than 500,000 - as well as the 183,000 people who signed up this week as registered supporters and the affiliated supporters in the unions.

He told Sky News: "I wish some of my colleagues would concentrate on political issues. I regret the language that's been used, by all of them.

"I don't do any abuse, I don't do any bullying, I don't allow it to be done anywhere to do with any of my campaign teams and I'm very surprised and very disappointed they should say that because politics has to be about bringing people in.

"I think we have done that spectacularly well; we now have the largest membership we've ever had. That's good, that means more and more people are involved in politics.

"That's good, it's not a threat, it's a good thing that people come together and want to debate and be active in politics in our society. Isn't that good for democracy?"

His comments follow an extraordinary claim from Labour whip Conor McGinn, who said Mr Corbyn considered calling his father Pat - a Sinn Fein councillor - in an effort to "bully" him following critical comments the MP made in a magazine interview.

Mr Corbyn's office dismissed the allegation as "untrue" but St Helens North MP Mr McGinn accused the party leader of hypocrisy for talking about a "kinder, gentler politics" when "he had proposed using my family against me".

He said: "The leader of the Labour Party was proposing to address an issue with one of his own MPs by ringing his dad."

Mr McGinn said he had decided to go public after watching an interview with Mr Corbyn in which he repeated his mantra of supporting a "kinder, gentler politics".

Mr McGinn said: "I am afraid I could no longer tolerate the hypocrisy of him talking about a kinder, gentler politics when I knew for a fact that he had proposed using my family against me in an attempt to bully me into submission because he didn't like something I said."

In a statement, Mr McGinn said he and other Labour MPs had been subjected to a "torrent of abuse and threats" from supporters of Mr Corbyn.

"In my constituency, a group of people gained access to my shared office building under false pretences and filmed themselves protesting outside the door of my office, in an incident that has been reported to the police," he said.

"They threatened to disrupt my surgeries and events I was attending, requiring me to have a police presence at those last weekend."

Meantime, former shadow cabinet minister Angela Eagle, who launched a leadership challenge against Mr Corbyn before standing aside to give Mr Smith a clear run, suggested the leader had contributed to abuse directed at her and her staff.

She has cancelled constituency surgery meetings, a brick was thrown through her office window and her local Wallasey constituency Labour Party has been suspended amid bullying claims.

Ms Eagle told the Daily Telegraph: "He has contributed to this. It's all very well to condemn it but there's a permissive environment. You can make any number of ritual condemnations as you like but you have got to be judged by your actions, not just words.

"He has been stirring, he needs to be held to account. We have contacted the police and they have said we should cancel surgeries for safety reasons."

Her colleague Harriet Harman, the former acting leader, has warned that Mr Corbyn is increasing division between rival Labour factions by threatening re-selection.

During his leadership campaign launch, Mr Corbyn confirmed all Labour MPs would face re-selection when new parliamentary boundaries - reducing the number of seats from 650 to 600 - come into force in 2018.

The move would pave the way for his supporters in the party's grassroots to push out critics by replacing them as Labour candidates.

Ms Harman told the BBC Radio 4 Today programme: "It's not clear whether what Jeremy Corbyn was saying was that there's going to be new measures in relation to preventing current MPs standing again as Labour MPs at the next election or whether he was describing the current system, but either way it's more of driving a wedge between different parts of the party, setting the members against MPs, setting MPs against members."

Elsewhere, Mr Smith said Labour was "failing in our duty to provide an effective opposition" as a result of the turmoil under Mr Corbyn's leadership.

In a letter accepting the nomination to stand in the leadership contest, the MP for Pontypridd said Labour was "letting the public down and undermining the democratic process" because of the inability to function effectively at Westminster.

He told Labour's general secretary Iain McNicol: "My promise to you and to the millions of people who hold the Labour Party dear is this: I'll campaign with integrity and decency at all times and I'll do everything I can to shape a future for Labour that's true to our core aims and principles."

Mr Smith claimed a "culture of bullying" has taken hold under Mr Corbyn's leadership as he warned the party could be "destroyed" and "consigned to history" unless it could unite.

Separately, the former shadow work and pensions secretary told Sky News that he had received death threats and the problem of abuse had not been there before Mr Corbyn's leadership win.

"I have never been bullied by Jeremy, Jeremy is...very softly spoken and very calm in his manner. But the problem is, under his leadership, there has been a culture of bullying, I fear. There has been intolerance in the Labour Party and abuse in the Labour Party that we have never seen before,” declared Mr Smith.

"Women in Labour have found themselves subject to awful, awful misogynistic abuse. Some of our Jewish MPs have been subject to anti-Semitic abuse and some of our Asian MPs have been subjected to abuse."

He added: "Jeremy, of course, always says that he doesn't condone it but somehow under his leadership - we can't deny the facts that this wasn't something that we saw in the Labour Party before Jeremy Corbyn became leader - and it's now become commonplace in the Labour Party. So something has gone badly wrong under his watch."

The Welsh MP revealed that his mother was one of the party's new registered supporters as he insisted they were not all going to back Mr Corbyn. However, it has been suggested that the 183,000 registered supporters eligible to vote split 60/40 in Mr Corbyn’s favour.