Shadow chancellor John McDonnell has accused the Government of being in “disarray” over Brexit on the eve of talks in Brussels.
But speaking on Sky News, former Tory leader and prominent Brexiteer Iain Duncan Smith has insisted the administration was united in its approach ahead of the start of negotiations on leaving the EU.
He pointed to comments made by Chancellor Philip Hammond that Brexit meant the UK would definitely be leaving the single market and customs union.
With the clock already ticking on the UK’s two-year departure from the bloc, Brexit Secretary David Davis will meet the European Commission’s chief negotiator Michel Barnier to hold their first formal Brexit talks on Monday.
They come after Theresa May lost her Commons majority as she sought a clear mandate from voters to strengthen her hand for the negotiations.
The election debacle has left her weakened and battling for her political survival.
Mr McDonnell told Sky News’ Sophy Ridge on Sunday programme: “I am afraid the problem with the Brexit talks is that we have a government in disarray.”
Claiming Mrs May’s administration was in a “complete mess”, he argued it should make way for a Labour government that would give a “clear direction”.
Pressed over his own party’s stance on Brexit, Mr McDonnell said: “Once you leave the EU, formally you are outside the single market.
“But what we are trying to get is tariff free access to the single market.”
He added: “I don’t care how we get it in terms of the structure as long as we get access to the single market tariff free and that means also we are not constrained by the existing rules of the single market and that’s obviously freedom of movement.
“The structures become immaterial to achieve the objectives.”
However, Mr Duncan Smith insisted there was support for the Government’s approach, arguing Labour had “almost exactly the same” manifesto commitment on Brexit.
He said: “The key thing is we have a clear agenda. We are united in that and just need to get on with it.”
Earlier, Mr Hammond told the BBC’s Marr programme: “We’re leaving the EU and because we are leaving the EU, we will be leaving the single market and by the way, we will be leaving the customs union.”
But he added: “It’s a statement of common sense that if we are going to radically change the way we work together, we need to get there via a slope, not a cliff edge.”
He also warned failing to secure a Brexit deal would be “very, very bad” for Britain.
Mr Hammond refused to say how long he believes the PM will remain in Number 10 as he criticised the way the general election campaign was run.