One of Europe's biggest populists is threatening to push UKIP to the brink of financial ruin

LONDON - The leader of one of Europe's most prominent populist parties is threatening to abandon the EU parliamentary group chaired by UKIP's Nigel Farage, a move that could cost the British pro-Brexit party around £1.3 million ($1.58 million) a year.

Beppe Grillo, the founder of Italy's Five Star Movement, is urging the party to terminate its alliance with UKIP by withdrawing from Europe of Freedom and Direct Democracy (EFDD), a Eurosceptic grouping within the EU Parliament, the Times reports.

The comedian-turned-politician Grillo launched an online poll on Sunday, which asked members whether they wanted to leave EFDD. The poll is set to close today.

The Five Star Movement currently has 17 MEPs in the Farage-led Eurosceptic group.

If the Grillo chooses to withdraw the populist party from EFDD, it will bring the group's membership down to just 27 representatives and, as a result, decrease the amount of annual funding it receives from the EU. The Times estimates that UKIP, currently led by Paul Nuttall, would lose approximately £1.3 million a year.

Grillo, whose anti-establishment party is quickly becoming the most popular opposition party in Italy, claimed that UKIP had achieved its mission by leading Britain out of the EU and therefore served no long-term purpose. The party's presence in the EU Parliament will come to an end in 2019 when Britain loses its MEPs as part of Brexit.

"Remaining in EFDD means facing the next two and a half years without a common objective, together with a delegation that is not interested in achieving concrete results," he wrote online.

The notion that UKIP has served its purpose has been widely discussed ever since the shock Brexit vote, despite the protestations of party members who believe that the Eurosceptic party can make progress in Westminster politics. Nuttall vowed to replace Labour as the "patriotic voice" of the working-class vote when he was elected leader in November.

Grillo's threat to abandon EFDD will be of huge concern to UKIP, which is reportedly already suffering from financial woes. The party is yet to repay to the EU the approximate £433,000 it wrongly used to fund its EU referendum campaign, while late last year it was forced to vacate its London headquarters amid rumours of financial struggles.

Arron Banks, who pumped over £1 million into the party during the reign of Farage, is yet to confirm whether he will continue to bankroll the party under the leadership of Nuttall. He told Business Insider that he would fund the party under the leadership of Diane James, but has so far been more ambiguous towards Nuttall.

Grillo's party could possibly join the Alliance of Liberals and Democrats for Europe (Alde), a liberal parliamentary bloc of 68 MEPs led by one of the EU's chief Brexit negotiators Guy Verhofstadt. A significant number Five Star Movement MEPs will likely shudder at the thought of aligning with a pro-EU alliance grouping, but doing so will insert the party into the Parliament's third biggest grouping and give it a great influence on decision-making.