Nigel Farage has said “bigots” and “extremists” are not welcome in Reform UK, as he seeks to “professionalise” the party after its election success.

Addressing its annual conference in Birmingham, the Reform UK leader said the party was “coming of age” after winning its first MPs in July.

But he conceded the party had not been “professional enough” to properly vet candidates, following a series of controversies over their past comments.

He added that the party represented the “silent majority” and could have won more seats, but that “amateurism let us down”.

Among proposed changes to make the party more professional, he said the party would be vetting candidates “rigorously” for all future elections.

He added that they would also seek to emulate the Liberal Democrats by aiming to win more seats on councils to bolster its national electoral chances, with a target to win “hundreds” of seats in local polls next May.

Reform UK, formerly known as the Brexit Party until the UK’s exit of the EU, won five seats at July’s election, giving it a foothold in Parliament.

Following its rebrand in 2021, it is aiming to become a permanent fixture on the right of British politics, with an emphasis on reducing immigration, tougher policies on crime and slashing taxes.

Now, it is aiming to overhaul its party structures, as it seeks to use its election performance as a platform to build longer-term electoral success.

Farage revealed ahead of the conference he would be giving up ownership of the party, which was set up as a private limited company to fast-track its creation ahead of the European Parliament elections in spring 2019.

Addressing delegates, Farage said the initial structure had allowed the party not to be infiltrated by “extremist groups”, adding that new political parties were often vulnerable to being “hijacked”.

He added: “We don’t want extremists, we don’t want bigots, we don’t want people who think that way, because we represent the silent, decent majority of this great country.”

Around 4,000 activists are attending the party’s gathering in the West Midlands, around four times as many as last year and its biggest yet.

To the sound of Eminem’s 2002 hit Without Me, which has become a familiar entrance tune for the Reform UK leader, Farage waved to activists as he lapped the auditorium at Birmingham’s National Exhibition Centre before his speech.

Farage, who was elected as an MP in July at his eighth attempt, was watched by the party’s other four MPs, including Lee Anderson, who sat on top of an open-top double decker bus inside the conference hall.

In his address, he told activists he was on a mission to “professionalise and democratise” the party, having given it a “beachhead” in Parliament.

He added the party would be “vetting candidates rigorously at all levels,” after dropping candidates during the general election following reports they had made offensive or racist comments.

“We haven’t got time, we haven’t got room for a few extremists to wreck the work of a party that now has 80,000 members and rising,” he added.

“We had the teenage tantrums which were those that caused us harm in the general election.

“But we’re now at a different point. The party is an adult, and this weekend, this weekend is when Reform UK comes of age.”

Speaking to reporters after his speech, he said voters had punished the party for “bad apples” among its slate of candidates, adding the final few weeks of the election campaign had been a “disaster”.

Although party managers will undertake vetting, in a post-speech interview with the BBC, he pledged that local Reform UK associations will “choose their own candidates” for future elections.

He added the branches would also be able to put new policies “on the agenda to be debated” at future conferences.

A new draft constitution, to be put to a vote on Saturday, would see the party’s board responsible, alongside the leader, for setting policy.

Motions approved by members would have to be debated within three months, but would only have “advisory force”.