To them, Tsipras is dangerous because he has pledged to tear up his country's controversial bailout pact with Brussels, despite saying he wants the country to stay within the euro.

CNN: What if Greece can't manage payback?

French economic policy is hemmed in by a fiscal pact where deficit targets are set in Brussels.

BBC: Italian election lessons for wider Europe

Faced with an opportunity last December to wring concessions out of Brussels in return for supporting the euro-zone Fiscal Pact, he opted to make highly technical, apparently innocuous but actually implausible demands relating to the City of London, including a veto over single market financial rules.

WSJ: Cameron Main Threat to Britain In Europe