The European Union (EU) would lose jurisdiction over its largest sea area if an independent Scotland is ejected - creating "an important security consideration" for member states, according to a former European Court judge.

Experts are divided over whether an independent Scotland would face a seamless continuation of EU membership or be ejected and face lengthy re-entry negotiations.

Sir David Edward, a leading expert respected by academics and MSPs alike, has said Scotland's case for seamless transition would be boosted by the "drastic" consequences of unpicking Scotland's EU rights and reassembling them.

He has challenged the "theory" espoused by European Commission president Jose Manuel Barroso and European Council president Herman Van Rompuy that Scotland would be a "new state" under EU treaties.

Sir David is making a much-anticipated appearance before Holyrood's European and External Relations Committee on Thursday.

Speaking ahead of the committee, he said: "It is useful to begin by considering the legal and practical implications of the Barroso/Van Rompuy theory.

"The theory seems to assume that at the moment of separation or on some other unspecified date the 'separating state', its citizens and its land and sea area would find themselves in some form of legal limbo.

"The state would cease, for example, to be constrained by the treaty rules in relation to the rates of VAT and corporation tax.

"Erasmus students studying there would become 'foreign students' without rights. Migrant workers would lose their rights under EU law to social security.

"The whole land and sea territory of the separating state would cease to be within the jurisdiction of the EU.

"In the case of Scotland, which probably has the largest sea area in the EU, that is an important security consideration quite apart from other considerations."

EU treaties provide for two years of negotiations to remove a member state that wishes to leave due to the inherent difficulties of unpicking its EU rights and obligations, he said.

He added: "The question of treaty interpretation that arises here is whether the same would apply to the far less drastic situation where an existing member state separates into two parts and both parts wish to continue membership?"

Sir David, who sat on European Courts for 15 years, describes himself as "a moderate unionist" who respects "the sincerely held views of moderate separatists".

At last week's committee, former Scottish Executive European director David Crawley expressed "the highest possible respect" for Sir David's views. Other experts have also deferred to his judgement at the committee.

First Minister Alex Salmond describes him as "someone whose authority cannot be questioned even by the Better Together parties" while Deputy First Minister Nicola Sturgeon said he "is not known to be a big supporter of independence, but he has a wealth of expertise on matters of European law".

However, his opinions have been challenged by former Deputy Solicitor to the Scottish Government Patrick Layden QC, who is also giving evidence to the committee.

"It seems now to be generally agreed that an independent Scotland would no longer be within the European Union and that amendments to the EU treaties would be required to admit Scotland to the EU," he said.

"In that regard I note Sir David Edward's query as to whether the correct legal analysis might not lead to the conclusion that both Scotland and RUK would effectively cease to be member states.

"I have some sympathy with that analysis, not least because I advanced it myself at an earlier stage, but two considerations lead me to think that it is unrealistic.

"First, there seems to be a general acceptance that RUK will continue as a member state and, in international law, general acceptance by other states carries a great deal of weight.

"Second, I would expect the internal UK legislation which recognised Scottish independence to make clear that the United Kingdom was continuing, and that Scotland was the separated entity."