Reform UK’s checks on candidates are “clearly not fit for purpose”, Labour has said after two more candidates in May’s local elections were accused of making offensive or potentially racist social media posts.

Meanwhile, it emerged that Restore Britain, the party set up by the MP Rupert Lowe after he left Reform, appeared to have accepted a donation from someone who has called publicly on social media for “another Hitler” to come to power.

Reform has faced a series of controversies about some of its candidates in the local elections in England on 7 May, as well as some people standing for the Scottish and Welsh parliaments, despite Nigel Farage saying the party had greatly improved its vetting.

Images of Facebook posts by Alan Stay, a candidate for Reform in the Isle of Wight, show he shared racist and sexist messages, including one that repeatedly used an explicitly racist epithet, arguing that it was not a harmful word. The post was made in response to a news story about a DJ losing their job for playing a record that featured the word.

Another candidate, Caroline Panetta, who is standing in the outer London borough of Bexley, retweeted anti-Islam comments, including one saying Sadiq Khan, the London mayor, wanted to turn the city into “Londonstan” where women would be unsafe.

In a post of her own, she claimed Islam was “the religion of rape, incest and paedophilia”. Other retweets concerned George Floyd, who was murdered by a police officer on a Minneapolis street in 2020, saying the murder conviction was a miscarriage of justice and calling Floyd a criminal.

Anna Turley, the Labour party chair, said: “What will it take for Nigel Farage to finally act? Farage has repeatedly boasted about Reform’s vetting procedures but it is still clearly not fit for purpose. Farage must condemn these vile remarks, sack them as Reform candidates and kick them out of his party without delay.”

Reform was contacted for comment.

Lowe left Reform last year after a bitter row with Farage. His new party is explicitly hard right, calling for millions of people to be deported from the UK. Recent polling shows it has about 4% support nationally.

The party has attracted support from openly racist and far-right activists, whom Lowe has declined to disown.

Among its supporters is an activist called Miles Routledge, who tweets under the name Lord Miles. In February he tweeted that he had become a member of a group of Restore Britain donors called the Cromwell Club, posting a photo to show the £2,500 donation that had achieved this.

Routledge has shown support for extremist views and this week called another Restore supporter, Steve Laws, a prolific far-right user of X, a “liberal” for wanting to deport millions of people from the UK, saying: “I have better solutions.”

In a post last July, he wrote: “What brings me joy and hope in this world is that by 2039 we’ll have another Hitler to lead another great uprising.”

Asked by the Guardian if he wanted to explain the posts, Routledge replied: “That’s exactly what I said and meant, and I was likely holding back.”

He added: “I must add that I will also imprison journalists such as yourself when I take an ounce of power.”