ROME (Reuters) - Italy’s maverick 5-Star Movement should cut ties with the anti-European Union UK Independence Party (UKIP) and consider hooking up with the Liberals in the European Parliament, 5-Star founder Beppe Grillo said on Sunday.

Beppe Grillo, the founder of the anti-establishment 5-Star Movement, talks during a march in support of the 'No' vote in the upcoming constitutional reform referendum in Rome, Italy November 26, 2016. REUTERS/Remo Casilli/File Photo - RTSUVBR

If the surprise switch goes ahead, it would see 5-Star enter mainstream European politics and move away from the anti-system fringes, a shift that might reassure other EU capitals that have grown uneasy about its rising popularity.

Writing on his blog, Grillo said his party was in talks with the Alliance of Liberals and Democrats for Europe (ALDE) and asked 5-Star members to back the initiative in an online ballot.

ALDE is headed by former Belgian prime minister Guy Verhofstadt. He is a keen European federalist and his strong, pro-EU views would seem at odds with the eurosceptic 5-Star, which has previously ridiculed the liberal leader.

Grillo said he had also approached the Greens about a possible tie-up, but was rebuffed, adding ALDE was the only group willing to discuss an accord with his movement.

The anti-establishment 5-Star won 17 seats in the last European election in 2014 and linked up with Nigel Farage’s UKIP, which had 22 seats, to form the so-called Europe of Freedom and Direct Democracy (EFDD) party.

But Grillo said the two parties had only voted together around 20 percent of the time over the past 2-1/2 years.

He added that UKIP had achieved its political goal when Britain voted last year to leave the European Union.

“To stay in EFDD would mean we would face the next 2-1/2 years without a common policy objective,” Grillo wrote.

UKIP’s Farage said he did not think 5-Star would survive long with the liberals. “In political terms it would be completely illogical for 5-Star to join the most euro fanatic group in the European Parliament,” he said in a statement.

Some 5-Star politicians also denounced the unexpected proposal, while Grillo’s opponents lambasted his strategic shift, saying he was looking to join the pro-EU establishment.

“What a pity. (5-Star) is moving from the barricades to the comfy seats,” said Matteo Salvini, the leader of the anti-euro Northern League, which is Italy’s third largest party.

5-Star was founded in 2009 and has risen rapidly to become Italy’s main opposition party. It does not fit into any clearly defined political ideology, focusing its energies primarily on denouncing corruption and political wrongdoing.

It has repeatedly called for a referendum on Italy leaving the euro single currency, and has criticized EU policy making, but says it does not want Italy to abandon the European Union.

Grillo said it was important for 5-Star to be part of an EU parliamentary group because that would give it greater visibility and influence. “Refusing to belong to a political group would mean ... not being able to work,” he wrote.

He added that by forging an alliance with Verhofstadt, ALDE would become the third largest group in the EU parliament. “This means that in many cases we would hold the balance of power.”