World Bulletin/News Desk

A surge in Euroscepticism in England has handed secessionists in Scotland a new weapon in their battle to break away from the United Kingdom: a warning that only independence can keep Scotland inside the European Union.

The Scottish National Party, which runs the devolved Scottish government, secured 29 percent of the vote in European elections, a slight dip from the 2009 vote but bucking a trend in England where the anti-EU UK Independence Party (UKIP) won.

Scottish nationalist leader Alex Salmond has already warned that the biggest threat to Scotland remaining in the EU is Prime Minister David Cameron's pledge to hold an in-out referendum on membership by the end of 2017.

Polls show Scots remain doubtful about breaking up the United Kingdom, but the worry for supporters of the union is that the rise of Euroscepticism could convince undecided Scots that a vote for independence on Sept. 18 is the only way to stay in Europe.

"The surge in support for the anti-EU party outside Scotland could push more wavering voters towards the Scottish independence campaign," said Holger Schmieding, chief economist of Berenberg Bank.

Breaking Scotland's 307-year-old union with England would rip out about 10 percent of the United Kingdom's gross domestic product, weaken British diplomatic clout and raise questions over its permanent seat on the U.N. Security Council.

While polls show Scots are so far unlikely to vote for separation, the proportion of those supporting independence has increased this year. Many are undecided.

EU MEMBER SCOTLAND?

Though Scotland is considered to be more pro-European than England, UKIP doubled its vote from 2009 to win its first Scottish seat in the election to the European Parliament.

Scottish nationalists won two seats, Labour two and the Conservatives one. The Liberal Democrats lost their only European seat in Scotland.

In England, UKIP won the European vote while in Wales Nigel Farage's party came a close second to Labour but beat both the Conservatives and Plaid Cymru, the Welsh nationalist party.

"With the rise of UKIP south of the border - where they secured three times the level of support they got in Scotland - it is more important than ever before that Scotland's distinctive voice is heard in Europe," Scottish Deputy First Minister Nicola Sturgeon said.

"That agenda is the exact opposite of what Scotland needs, which is why we need to build our own relationship with our European neighbours as an independent country - something that only a Yes vote in September can secure."

But the SNP may have to calibrate its message on Europe as one survey found Scotland may not be completely isolated from the European surge in Euroscepticism.

A higher proportion of SNP supporters favoured leaving the EU than voters for the Conservatives or the Labour party, a survey by Dundee University showed.

It also found that more of those who supported independence wanted to leave the European Union than those who opposed independence.

European Commission President Jose Manuel Barroso has said that states breaking away from existing EU countries would struggle to gain EU membership, though Salmond says an independent Scotland could negotiate membership of the EU and would not have to re-apply.