FORMER Conservative chief Iain Duncan Smith has called on Theresa May to stand down as soon as next month as he called the party’s failure to leave the EU on time “a disaster”.

He told Sky’s Sophy Ridge On Sunday: “I know that the Prime Minister has already said she’s going. She said she would go as and when the agreement was ratified which was looking at around about May, June. I think those dates still stand.

“I think that what the PM has to do is aim everything now towards departure before the Euros (elections) which would then allow her to step away having done what she said she would do, getting the UK out of the European Union one way or the other and then we can have another leadership election and pick a new leader which is the way it has to be.”

The Conservative grandee said opinion polls – with one yesterday forecasting a Labour win in a snap general election and the Tories losing 60 seats – were currently concerning and blamed the delay to Brexit past March 29.

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“It was on the 29th when we didn’t leave that’s when this has all gone wrong up until then people were prepared to give Theresa May the benefit of the doubt,” he said.

“The big problem was as soon as we didn’t leave you could see all the poll ratings start to crash.

“And it’s wholly linked to the fact that to Leave or Remain they were all expecting us to go and when we didn’t go it looked like a complete breach with the pledge that we had made and that’s a disaster for a political party.”

The National: Theresa May

May promised Tory MPs at the end of March – ahead of the third meaningful vote on the EU withdrawal agreement in the Commons – that she would quit if they backed her Brexit deal.

She did not name a departure date at a packed meeting of the 1922 committee of backbench Conservative MPs.

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But reports suggested if the deal was passed she would resign as party leader after May 22 – the expected Brexit date at the time – but stay on as PM until a new leader is elected.

However, she failed to get backing for a third time for her deal, prompting her to open talks with Labour leader Jeremy Corbyn for an alternative way forward to break the impasse – and seek a further extension to the Article 50 process of leaving the EU.

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Last week EU leaders gave May a potential new Brexit deadline until October 31, though the PM insists she still hopes to get a Brexit deal passed by May 22 to avoid the UK taking part in elections to the European Parliament the following day.

Duncan Smith is the latest Tory Brexiteer to call for May to stand down over the delays to leaving the EU. She faced calls for her to go from angry Tory backbenchers last Thursday following the latest Article 50 extension.

In one dramatic moment in the Commons Tory MP Sir Bill Cash asked May to account for her “abject surrender” in Brussels, and to resign.He said: “Does the Prime Minister appreciate the anger that her abject surrender last night has generated across the country, having broken promises 100 times not to extend the time?”

Cash asked if May accepted her Brexit deal “undermines our democracy, the constitutional status of Northern Ireland, the right to govern ourselves, control over our laws, and undermines our national interest?”, adding: “Will she resign?” But May shot back: “I think you know the answer to that.”

Chancellor Philip Hammond has suggested May will stay on until October, saying she had no intention of leaving before the first stage of the Brexit process is complete.