EXTENDING the timetable for Brexit negotiations must remain on the table if the UK is to "avoid an economic cliff-edge", Nicola Sturgeon has warned.

At the same time as Theresa May was insisting that delaying the UK's March 29 European Union departure date was "not an option", the First Minister urged Westminster to take an "urgent reality check".

Ms Sturgeon has written to opposition leaders in London, arguing that if the UK failed to agree a deal with the EU, the timetable for talks must be extended.

The SNP leader said: "It's time for everyone in the UK political establishment to wake up to the reality of what now faces us.

"If the choice we face is between no-deal and no detail, then an extension to the Article 50 negotiation period must be on the table as the only way to avoid an economic cliff edge, and allow all alternative options to be considered."

At a dinner with fellow European leaders in Salzburg, Austria, on Wednesday night, Mrs May continued to argue her Chequers proposals were the only credible route to a deal.

The PM's message was that while the time for an agreement to be reached was now short, "delaying or extending these negotiations is not an option", according to a senior UK official.

Mrs May has been adamant that there will be no second referendum on Brexit nor any extension to Article 50 ie Britain will leave the EU on March 29 next year.

But the FM insisted it "seems increasingly likely" that the statement setting out the future relationship between the UK and the EU "will be vague and lacking in meaningful detail".

"The Tory Government has been busy trying to paint Brexit as a choice between a no-deal Brexit and the inadequate Chequers proposal, but in reality that is a false dichotomy; thanks to their incompetence, infighting and indecision, it seems increasingly likely that the choice will be between a no-deal Brexit and a blind Brexit.

"Both options are unpalatable and completely unacceptable,” declared Ms Sturgeon.

"A no-deal Brexit will, by the UK Government's own admission, lead to dire economic consequences and a shortage of medicines and foodstuffs.

"Meanwhile, a blind Brexit will simply kick all of the difficult decisions into the long grass - but with the UK already out of the EU.

"Not only would that continue the uncertainty, it would be tantamount to stepping off a cliff edge blindfolded, with no idea of what the landing place will be."

Ms Sturgeon added: "Even at this late stage, Theresa May can escape the corner into which she has boxed herself. For two years, the Scottish Government and many others have been telling the Prime Minister that by far the least damaging Brexit option would be to remain in the single market and customs union; it is time for her to listen."