Senior Ukip figures including Nigel Farage have expressed disquiet at the hard-right direction chosen for the party by its leader, Gerard Batten, and his open support for the jailed anti-Islam activist Tommy Robinson.

While Farage did not openly criticise Batten, the former party leader told a meeting of Ukip activists that being seen as opposing all Islam and backing Robinson was a political mistake.

Other concerns, so far expressed privately, have increased in intensity after supporters of Robinson clashed violently with police on Saturday following a march in central London backing the jailed founder of the English Defence League (EDL), a far-right group.

It is understood one senior party member wrote to Batten to express unease about his anti-Islam stance, with others considering a similar move.

Batten, a Ukip MEP, took on the leadership on an initial one-year basis without a contest in February, after his predecessor Henry Bolton was removed amid controversy about offensive messages sent by his girlfriend.

Batten, the Ukip leader, has previously described Islam as a ‘death cult’. Photograph: Dominic Lipinski/PA

Batten was already openly anti-Islam, having described the faith as a violent “death cult”. After becoming leader, he called for Muslims to be asked to sign a document renouncing parts of the Qur’an.

He has since openly supported Robinson, despite a longstanding Ukip rule aimed at preventing far-right infiltration, which bars former EDL members from joining. He has been interviewed by Robinson’s YouTube channel and spoke at a “free speech” protest in London organised by him.

Robinson, whose real name is Stephen Yaxley-Lennon, was jailed in May for 13 months for contempt of court after using social media outside Leeds crown court to broadcast details of a trial subject to reporting restrictions.

On Saturday, activists blocked roads and clashed with police near Trafalgar Square. Five officers were injured, with nine people arrested.

Batten, who has repeatedly expressed his view that Robinson should not be in prison, had tweeted that he was going to speak at what he called a “free Tommy Robinson rally”. He blamed the violence on “a few idiots and provocateurs”.

Today I will be speaking at the Free Tommy Robinson Rally at Whitehall at 3pm. pic.twitter.com/H3Iy4EkezY — Gerard Batten MEP (@GerardBattenMEP) June 9, 2018

Farage’s comments, seen by the Guardian, came in an address to a dinner of Ukip activists in Lancashire this month. He said the party was right to oppose Islamic extremism. “But if dealing with Islamic fundamentalism becomes a battle between us and the entire religion, I’ll tell you the result: we’ll lose. We will simply lose,” he said.

“We absolutely have to get that Muslim majority living in many of our towns and cities on our side, more attuned to western values than some pretty hardline interpretations of the Qur’an.”

Farage added in an apparent criticism of Batten: “I think this gets to the heart of not just the positioning of a political party, but of judgment too. And judgment really, really matters. Tommy Robinson is seen to be a hero by many. But actually, what the bloody hell was he doing outside the court?”

One senior Ukip figure of long standing, speaking anonymously, said there was a wider worry about Batten’s liaison with Robinson.

“These are the people we spent years trying to keep out of the party, and so this isn’t making a lot of people happy,” they said. “It’s really upset what you might call the more old-school party members.”

Another party source said it would “not be a complete surprise” if any more Ukip MEPs resigned the party whip. Two have already done so, although before Batten became leader.

Another senior party figure said it could be hard to gauge unhappiness in an already demoralised and shrunken party, which won almost 4 million votes in the 2015 general election, but has seen support plummet since then under a series of short-lived leaders.

A recent poll gave the party less than 3% support.

There was no official response from the party. However, it is understood that Batten has explained his view as being that he does not support Robinson’s beliefs, but believes Robinson has seemingly been treated more harshly in his sentence than would be the case for others.