European Union leaders are downplaying an independent Scotland's right to EU membership, to compel it to join the euro, open its borders and pay more towards the European budget, according to a senior German government adviser.

EU treaties are "consistent with automatic succession of both the seceding state and the rump state" but international leaders "have a vested interest in centralisation" and "are biased against secession", said Professor Dr Roland Vaubel, an adviser to Germany's economics ministry.

A string of European leaders, including EU commissioner Jose Manuel Barroso, vice-commissioner Viviane Reding and EU Council president Herman van Rompuy, have suggested Scotland would need to reapply as a new state if it left the UK.

Dr Vaubel said their position was based on a desire "to renegotiate the terms of Scottish membership", to bring them into the euro and Schengen borderless-travel area and give up the budget rebate negotiated by Margaret Thatcher in 1980s.

But he said such arguments had "no basis in the European treaties".

Dr Vaubel believes Secession can be a positive force in western democracies, encouraging competition and improving the rights of citizens, In the October edition of the journal Economic Affairs he says: "The opinion of the European Union institutions that Catalonia and Scotland, after seceding, would have to reapply for EU membership has no basis in the European treaties. Nor has this question been settled in any UN agreement or Vienna Convention.

"Secession strengthens competition among governments. By putting the politicians and bureaucrats of different countries under competitive pressure, secession improves their performance."