Andrea Leadsom has called a recording of John McDonnell repeating abuse about a Tory cabinet minister “truly evil” as Jeremy Corbyn came under fresh pressure to condemn the comments.

The Commons Leader criticised the Labour leader directly on Twitter after the BBC broadcast a recording of the comments about Esther McVey from 2014.

Mr Corbyn and senior Labour MPs suggested they did not condone the language repeated by the shadow chancellor, but that they disagreed with Ms McVey’s role in welfare reform.

It came as the Tories announced that all its candidates would sign a new pledge to behave responsibly and treat people with respect online.

A recording of Mr McDonnell, obtained by BBC Sunday Politics, shows him quoting others who called for the “lynching” of Ms McVey, who was at the time the minister for disabled people.

Ms Leadsom wrote on Twitter: “This is truly evil. Utterly disgusting.

“The laughter about launching a campaign against @EstherMcVey1 on her birthday, and then the guffaws about killing her. Seriously?

“Is this @jeremycorbyn ‘s kinder, gentler politics? This has to stop.”

Mr Corbyn was challenged over separate comments by Mr McDonnell, who also called new Work and Pensions Secretary Ms McVey “a stain on humanity” when he was a backbench MP.

“I would rather stick to where I disagree with somebody on their policies,” Mr Corbyn told ITV’s Peston On Sunday.

“I fundamentally disagree with Esther McVey and her approach towards inequality and the poor and the worst off within our society and I will stick to that.”

Brandon Lewis, the new Tory Party chairman, told BBC1’s The Andrew Marr Show that Tory candidates who breached the pledge about online behaviour would be suspended, as he called on Labour to “make the same statement”.

Mr Corbyn said treating people with respect was “a basic” in the Labour Party and he did not engage in personal abuse.

“Given Jeremy Corbyn again refused to condemn the inappropriate comments from his shadow chancellor, it is no surprise he has refused to sign up to this respect pledge for future elections,” said Mr Lewis.

“This shows more than ever that the rot is at the top of the Labour Party.

“Abuse has no place in our democracy and we will condemn it wherever it arises, Jeremy Corbyn needs to do the same.”

Mr Lewis has also urged his party to beef-up its digital presence to take the fight to Labour.