Martin Schulz, former president of the EU parliament, said that he doubted Spain would be enthusiastic about an independent Scotland

An independent Scotland would face a “very long, hard debate” in its attempt to rejoin the EU, a former European parliament president has said.

Martin Schulz, who was president of the parliament during the 2014 independence campaign, said that EU member states were “hard and tough” on secessionist movements. The Spanish government would make Scottish accession difficult to discourage Catalan nationalists from making a similar move, he suggested.

Keith Brown, the SNP depute leader, said on Thursday that the Spanish government had made it clear it would not obstruct Scottish membership.

The Scottish government’s white paper on independence anticipated “a smooth transition to independent membership” within 18 months.

Mr Schulz told BBC Newsnight: “As a former president of the European parliament, I