The SNP 's Westminster leader has warned that opposition MPs could struggle to block a no-deal Brexit.

Ian Blackford said any proposition to halt Brexit by revoking Article 50 would have to have teeth and currently it is not clear that would be "particularly easy" to do.

Chancellor Philip Hammond earlier warned Conservative leadership candidates they will not be prime minister for long if they pursue a no-deal Brexit, hinting that he and other Tories could be prepared to vote down the government in a confidence motion to prevent that outcome.

Speaking on BBC's The Andrew Marr Show,  the chancellor reminded hardline Brexit candidates Boris Johnson, Dominic Raab and Esther McVey that parliament was “vehemently opposed” to leaving the EU without a deal.

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Mr Blackford, meanwhile, said a no-deal Brexit would "crash the economy" and that Theresa May's resignation means an increased threat of leaving the EU without a deal as a default on October 31.

He said: "What we're seeing at the moment seems to be a lurch to the right from the Conservative Party, they all seem to be outdoing each other on the no-deal Brexit stakes.

"I think, at the end of the day, there seems to be a very real risk to the people of Scotland, not just the people of Scotland but the people of the United Kingdom, in terms of that no-deal scenario."

He called for a general election, a people's vote and for Article 50 to be revoked.

"We need to make sure we can give teeth to any proposition to revoke Article 50, and at the moment it is not clear that, if the Government doesn't bring forward legislation, it's going to be particularly easy to do that," he added.

HeraldScotland:

"What Theresa May was talking about was bringing forward a Bill that would be become an Act of Parliament and of course that could be amended and then would give us the option to revoke Article 50 but we simply don't know at this stage what a new prime minister will do."

Asked if any prime minister determined to take the UK out of the EU could do so by the default date by not doing much at all, Mr Blackford said: "I'm afraid that is the case. I know that sounds absolutely ridiculous but ... that is the default position.

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"That's where we are from the legislation that is already in place so we have to find a way to stop that.

"The best way of doing it, in many respects, is if the new prime minister does bring forward legislation, but on a no-deal basis that it's possible they could avoid that.

"So we are in a very dangerous, very worrying situation in terms of our future as members of the European Union."

Meanwhile former Brexit Secretary Dominic Raab told The Andrew Marr Show: "I will fight for a fairer deal in Brussels ... if not I will be clear we will leave on WTO terms in October.

"If you're not willing to walk away from a negotiation, it doesn't focus the mind of the other side I will not ask for an extension."

Shami Chakrabarti, Labour’s shadow attorney general, said Mr Raab's comments were “terrifying”, adding: “It will be terrifying for a lot of viewers at home.”

And Esther McVey said: "October 31 is the key date and we are coming out then, and if that means without a deal then that's what it means."

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International Trade Secretary Liam Fox meanwhile said he believed a "determined" Prime Minister could defy objections in the Commons and take the country out without an EU agreement.

"There is a chance that parliament could try to stop a no-deal," the Scot told the BBC's Pienaar's Politics show.

"A very determined Prime Minister could probably, by using time, get to no-deal even if parliament didn’t want it.”