THERESA May has received a glimmer of support for her preferred post-Brexit customs plan from the Irish Taoiseach as Jeremy Corbyn claimed Cabinet divisions meant the EU withdrawal talks were a “shambles”.

After a majority of the Prime Minister’s senior colleagues last week rejected the customs partnership plan and Boris Johnson, the Foreign Secretary, dismissed it as “crazy,” Leo Varadkar suggested it might just work.

The Irish PM said the proposal whereby the UK would collect EU tariffs and then rebate member states was a “welcome suggestion”.

“The view of the EU is that it isn’t workable in its current form but it is something that perhaps we could make workable,” he explained.

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Downing Street, when asked about the Taoiseach’s intervention, declined to comment.

In the Commons, the Labour benches taunted Mrs May over Mr Johnson’s comments, which some Conservative colleagues believe was meant to undermine her premiership.

Mr Corbyn asked if the PM agreed that the customs partnership plan was crazy, noting how her Business Secretary, Greg Clark, had backed it at the weekend.

Mrs May again insisted Britain would leave the customs union and have an independent trade policy.

But she returned fire, telling the Labour leader: “I'll tell him what's crazy…a Leader of the Opposition who for years opposed TTIP [the Transatlantic Trade and Investment Partnership] and now has a policy [creating a new customs union] that would mean Labour signing up to TTIP with no say in it whatsoever."

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The Labour leader later quoted Ken Clarke, the former Conservative Chancellor, when he asked the PM if she would stand up to the "wild right-wing people".

Mrs May responded by stressing how Labour’s customs union plan would mean the UK having no say over trade policy with Brussels negotiating trade deals in their interest, not Britain's.

However, the PM faced barracking from the Labour benches as Mr Corbyn declared:“Due to divisions within the Government these negotiations are in a shambles."

The SNP’s Ian Blackford also attacked Mrs May over the Foreign Secretary’s rejection of her preferred customs plan, urging her to have the “backbone to send Boris Johnson to the backbenches”.

Later, the Secretary of State told MPs he was "completely in conformity" with the Government's Brexit policy as the customs approach had yet to be decided.

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While the so-called War Cabinet is due to meet later today, it is thought the refinement and improvement process on the options is likely to mean the main showdown will not come until next week.

After PMQs and in wake of the 83-strong rebellion by Labour peers calling for Britain to stay in the European single market, the party’s HQ suggested the leadership would adopt the same approach when the issue returned to the Commons for a vote next month ie abstention.

Mr Corbyn’s spokesman said: “By our whipping for abstention, we’ve made quite clear that we favour a new relationship with the single market. We favour negotiating a new customs union with the EU with a British say in future trade deals and that’s why we took that position.”

Asked if the leadership would order its MPs to abstain, the spokesman replied: “Whipping arrangements are decided nearer the time but from what I’ve said you can see what our priorities are. We’ve indicated in what we’ve already done what position we will take on that."

A Labour abstention is likely to mean Mrs May will win the vote as the Opposition is set to be badly split on the issue.

Scottish Labour MPs Ian Murray and Martin Whitfield indicated they would lead the rebellion.

In a joint statement, they urged their party’s leadership to “stand up for workers and defeat Theresa May’s destructive Brexit”.

They added: “We know we will be joined by many of our party colleagues from England and Wales, other opposition parties and a number of Tory MPs. If the Labour leadership wants to we can now stop a hard Brexit in its tracks.”