Image copyright PA Image caption The shadow chancellor has issued an "open invitation" to MPs

"We have begun our tea offensive."

So say the team around the Shadow Chancellor John McDonnell, as they emphasise the need for "unity" in the Labour Party.

"The biggest fear the Tories have is a united Labour Party," a source close to Mr McDonnell said.

"Jeremy Corbyn could be the most transformative Labour prime minister since Clement Attlee."

The shadow chancellor addressed Labour MPs at their weekly meeting in Parliament earlier on Monday.

Sources said he showed "contrition" over an article he wrote suggesting there was a "soft coup" under way designed to topple Jeremy Corbyn.

"We must focus on unity," he told Labour MPs, singling out for praise previous critics of Mr Corbyn such as Rachel Reeves and Angela Eagle.

John McDonnell has issued "an open invitation to anyone" in the Labour movement who would like to talk to him and have a cup of tea, but sources wouldn't say if they were dispatching invitations directly, or merely accepting requests to meet him.

But not all MPs in the room were convinced.

'Droning on'

One told me he asked Mr McDonnell, in a reference to Sir John Major's speech about Brexit: "Why is a former Tory Prime Minister more effective at attacking a Tory government than a Labour shadow chancellor?"

Another walked out 15 minutes before the end muttering "they'll still be droning on this time tomorrow".

Mr McDonnell used his briefing to Labour MPs to set out what his priorities will be in response to Wednesday's Budget.

Labour will have four themes they will question the government on: what they see as "chronic low pay;" a "rigged economy in favour of the privileged few;" social care, where "one million people are going without the care they need" and "ensuring the economy works for women."

Referring to Mr Corbyn's recent publication of his most recent tax return, a source said Mr McDonnell "has a genuine worry for democracy in this country" since "the prime minister and chancellor have still not published their tax returns."

"You have a level of transparency at the top of the Labour Party that you don't have in government."