Theresa May has been slammed by the SNP for getting into a "catastrophic negotiating position" on Brexit days after civil service papers outlining a "Doomsday" no-deal scenario were leaked.

The party's Westminster leader Ian Blackford MP questioned the Prime Minister about the contingency planning document, details of which were provided to the Sunday Times.

It pointed to the potential for food, fuel and medicine shortages and the collapse of the port of Dover on "day one" if Britain leaves the EU without a free trade deal.

Officials from three UK Government departments reportedly drew up the plans last month, outlining three scenarios in the event of a no-deal Brexit: one "mild", one "severe" and one described as "Armageddon".

A source told the newspaper: "In the second scenario, not even the worst, the port of Dover will collapse on day one.

"The supermarkets in Cornwall and Scotland will run out of food within a couple of days, and hospitals will run out of medicines within two weeks."

Raising the report during Prime Minister's Questions on Wednesday, Blackford also cited official advice to Dutch businesses advising them to avoid using British parts for products, such as car components.

The Dutch Government was responding to EU guidance telling exporters that UK parts and goods will not receive preferential tariff treatment if no trade deal is reached with Britain.

The Prime Minister told Blackford there was no change to plans for a trade deal with Europe, adding supermarket chains in Scotland said it was "important" to remain part of the UK.

Blackford said: "Supermarkets running out of food within days, hospitals running out of medicines within a fortnight, petrol reserves dwindling after just two weeks: these are the concerns of UK Government officials.

"And now the Dutch are telling Dutch businesses not to risk buying UK products."

He asked May: "Does the Prime Minister understand the catastrophic negotiating position she has cornered herself into?"

The SNP MP also urged May to back House of Lords amendments to the EU Withdrawal Bill to keep Britain in the customs union and European Economic Area (EEA).

The Prime Minister replied: "As we've already set out is our ambition for that trade deal with the European Union in the future.

"But he refers to the wishes and desires of... supermarkets in Scotland and supermarkets across the rest of the UK.

"Of course, he might pay attention to the supermarket chains in Scotland who said that one of the most important things for Scotland is to remain in the United Kingdom."