The pressure mounts on Greece’s prime minister this week, with the second round of a three-stage presidential vote taking place tomorrow.

Fears of 'Grexit' – Greece exiting the euro zone – were revived in recent weeks, rattling investors, after Antonis Samaras took a political gamble by bringing forward the election for a new head of state by two months.

If Mr Samaras’s coalition government is to survive, he must secure victory for his presidential candidate – former European environment commissioner Stavros Dimas – by the final round of voting next week. Otherwise parliament will be dissolved and snap national elections triggered for the end of January, with the far-left Syriza party – which is strongly opposed to Greece’s EU-IMF bailout deal – tipped to win.

Why is the centre-right prime minister playing such a high-stakes game that risks toppling his own government? He made the decision amid heightened political uncertainty over Greece’s transition from its bailout.

The logic seems to be that if the government can get its presidential candidate elected, it demonstrates that it has sufficient support to push through tough reforms, paving the way for Greece to exit the programme.

“We shed blood to take the word ‘Grexit’ away from the mouths of foreigners and Syriza is bringing this word back to their mouths,” Mr Samaras told his party earlier this month. “All MPs must now decide if we will elect a president or go to snap elections that people don’t want, the markets are afraid of and which might have catastrophic consequences for the country.”