THE SNP have promised to set out before the next independence referendum what they believe Scotland’s future relationship with Europe should be.

Responding to the 50 MEPs who wrote an open letter saying Scotland would be “most welcome” to rejoin the EU in the event of independence, Bruce Crawford, writing on behalf of the SNP group at Holyrood, said his party would: “set out well before any referendum how our future relationship with Europe will be secured in the event of independence, giving those living in Scotland an informed choice”.

Though strong supporters of the EU, the party have been careful so far not to bind a second independence referendum to membership of the EU. However, Nicola Sturgeon has said her preference is an independent Scotland as part of the bloc.

In the letter, Crawford thanks the MEPs for their offer of support “in ensuring a swift, smooth and orderly transition of an independent Scotland into the family of independent European nations if Scotland chooses that future in a democratic referendum”. He also says a second vote on Scottish independence is being sought because of “the intransigence of the UK Government which has brought us to this juncture”.

Crawford goes on: “The Scottish Government offered a serious compromise plan, which was completely disregarded by the UK Government. However, we still risk being dragged out of the world’s largest single market by a Tory Government that Scotland rejected and, as you rightly recognise, in spite of the fact that Scotland voted overwhelmingly to remain within the EU in last June’s referendum.”

He adds that “the depth of goodwill from across Europe is indeed heartening as we embark on that process and we look forward to continued close cooperation in the months and years ahead.”

The letter from the 50 MEPs was organised by Green MSP Ross Greer. In it, the European politicians said: “If Scotland were to become an independent country and decided to seek to maintain EU membership, we offer our full support to ensure the transition is as swift, smooth and orderly as possible.

“Scotland would be most welcome as a full member of the EU, with your five million European citizens continuing to benefit from the rights and protections we all currently enjoy.”

Earlier this month Spain said it would not veto an attempt by an ind- ependent Scotland to rejoin the EU.

Meanwhile, the shipping industry has warned of “absolute catastrophe” unless the UK Government sorts out a post-Brexit system for Britain’s ports. The UK Chamber of Shipping, which represents more than 170 freight ship, tanker and cruise liner companies, has called on governments across Europe to urgently grasp the challenge.

Guy Platten, the head of the organisation, warned that the introduction of physical customs checks would likely lead to a reduction in the volume of trade, and huge delays in ports throughout Europe.

“The nightmare scenario is actually having physical customs borders ... it would be absolutely a catastrophe for the ports and for our sector,” Platten said yesterday. “You’ve suddenly got lorries stacked up, you have sailings cancelled ... the whole supply chain is completely affected.”

The chamber says 95 per cent of Britain’s international trade is moved via ship, and the industry supports 250,000 jobs. Scotland’s largest container port is Grangemouth.

More than three million containers have passed through it over the past 50 years, and each year it handles more than £6 billion worth of goods each year including spirits, food, steel plate, timber, paper and equipment for the oil and gas industry.

According to its owners, Forth Ports, as much as 30 per cent of Scotland’s gross domestic product (GDP) goes through Grangemouth. Platten warned that if EU trucks travelling by ferry faced the same customs checks as non-EU trucks going through ports. the whole process will be slowed, particularly impacting goods such as fresh food, he added.

“The sailings will still take place, but maybe they won’t be able to fit in as many sailings as they could before ... so that will affect the business of those ferry companies and potentially the viability of routes.”

The chamber, which represents 170 firms including European companies such as Sweden’s Stena Line, Denmark’s DFDS and France’s Brittany Ferries, says the volume of lorries passing through Dover increased by 150 per cent between 1992 and 2015. Customs controls within the EU were scrapped from 1993.

Platten said the Government needs to reach an early agreement on customs, or ensure a transition period, as checks will require new infrastructure that will take time to put in place and which British ports will struggle to accommodate physically.

He believes the British Government will be prepared to apply a light touch at its border to prevent huge queues of trucks and hopes EU shipping firms will persuade their own governments to do the same.

“I am in no doubt [ministers] want to deliver,” Patten said. “They don’t want [extra checks] to happen”