Jeremy Corbyn has branded the prospect of a “no deal” Brexit amid Conservative uncertainty the “biggest risk” facing the UK.

The Labour leader attacked Theresa May for failing to manage her Cabinet which is “split down the middle” and said it was time to get a grip on her govern in order to end the Brexit confusion.

“That gives the whip hand to grandstanding EU negotiators. One week the Home Secretary says a ‘no-deal’ exit from the EU would be ‘unthinkable’. The next week the Brexit Secretary insists ‘no deal must be an option’.”

He claimed the Conservatives were using Brexit as a “device to drive down wages and conditions, deregulate consumer and environmental protections and slash corporate taxation in a destructive race to the bottom”.

The Islington North MP said the Brexit talks were currently at a “crucial” stage but the Tories’ “chaotic dithering” risked a “jobs meltdown” if the UK were to crash out of the union with no deal and job-creating investment decisions are delayed or moved to another country.

He said that Labour is instead proposing a “jobs-first” Brexit which will include “a new co-operative relationship with Europe” and a “time-limited transitional deal on the same basic terms as now”.

Mr Corbyn called on Ms May to get a grip on her government, he said it was time for her “to stop dithering and decide” whether to govern or “move out of the way and let Labour deliver a Brexit that works for the many, not the few”.

He also castigated Foreign Secretary Boris Johnson for his many interventions on Brexit including his 4,000 word opinion piece in the Daily Telegraph in September where he laid out his own plan for leaving the EU.

Brexit: the deciders Show all 8 1 /8 Brexit: the deciders Brexit: the deciders European Union's chief Brexit negotiator, Michel Barnier Getty Brexit: the deciders French President Emmanuel Macron Getty Brexit: the deciders German Chancellor Angela Merkel Reuters Brexit: the deciders Commission President Jean-Claude Juncker EPA Brexit: the deciders The European Parliament's chief Brexit negotiator Guy Verhofstadt Getty Brexit: the deciders Britain's Prime Minister Theresa May Getty Images Brexit: the deciders Britain's Chancellor of the Exchequer, Philip Hammond PA Brexit: the deciders After the first and second appointed Brexit secretaries resigned (David Davis and Dominic Raab respectively), Stephen Barclay is currently heading up the position PA

He said Mr Johnson should “be focusing on his day job” and Ms May should “ensure the Foreign Secretary can cause no further damage to our citizens abroad”.

He was talking about the controversy surrounding Mr Johnson’s remarks about the fate of British-Iranian Nazanin Zaghari-Ratcliffe who has been detained in Iran.

Ms Zaghari-Ratcliffe was sentenced to five years in prison in Tehran for undisclosed crimes but her plight was made worse by Mr Johnson wrongly claiming she had been in the country training journalists – she was on holiday visiting her parents with her young daughter.