Robinson, whose real name is Stephen Yaxley-Lennon, is the founder of the English Defence League, which has staged violent demonstrations against Islam.
Under current UKIP party rules, he is barred from joining the party, leading party leader Gerard Batten to appoint him as an adviser in a personal capacity.
“It is not necessary for him to be a party member in order to assist me in this role. I am looking forward to working with him,” Batten said, according to the BBC.
UKIP currently has no members of parliament in Westminster, but was an influential voice in calling for a referendum on European Union membership, and campaigning to leave, under former leader Nigel Farage.
The party has splintered since the June 2016 vote to leave the EU and underwent a lengthy struggle to find the right leader to replace Farage.
Batten has pushed a more anti-Islam message since, and some have criticized his engagement with far-right figures.
Farage told the BBC Radio that Batten’s appointment of Robinson risked tarnishing the party and possibly the whole Brexit process.
“From every single aspect, it’s time we got rid of Gerard Batten and reclaimed the party,” Farage said.
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