Former British foreign secretary David Miliband has hinted that Scotland would not automatically join the European Union (EU) if it becomes independent after a referendum in 2014.

Miliband made the remarks during a visit to Scotland on Friday.

Leaving the UK would leave an independent Scotland "in limbo in Europe," he was quoted by the Scotsman newspaper as saying on Saturday.

There would have to be "detailed and forensic negotiations" between all the current member states before Scotland could be admitted to the EU, Miliband said.

Miliband also warned that an independent Scotland could find itself in a similar position as Croatia, which is poised to join the EU next year after a decade-long battle for membership.

The process for admission to the EU was long and tortuous, said the former British foreign secretary in the Labor government.

The 35 chapters of EU legislation have to be gone through line by line and all EU countries have to agree on every line, Miliband said.

"The final part is that you have to get agreement of all 27 countries, soon to be 28, of all ministers, and then it has to be ratified by each country," he said.

On Friday night, a spokesman for Deputy Scottish First Minister Nicola Sturgeon disputed Miliband's claims, noting that the automatic entry had been confirmed this week by a leading expert.

Graham Avery, an honorary director-general of the European Commission, gave his evidence to Westminster's foreign affairs committee, stating that for practical and political reasons, Scotland could not be asked to leave the EU and apply for readmission.

In October, Scottish First Minister Alex Salmond claimed that an independent Scotland would automatically become an EU member, while opting out of the euro.

But Sturgeon admitted later that while Edinburgh had previously cited "eminent legal authorities" on the issue, it had not until late October sought a specific ruling from law officers.

Facing increasing pressure from opposition parties, Salmond had asked for an investigation into whether he, as he repeatedly claimed, had formal legal advice about Scotland's EU membership and so breached the ministerial code.

British Prime Minister David Cameron and Salmond signed the Edinburgh Agreement in October, allowing Scotland to hold an independence referendum in autumn 2014.