British National Party (BNP) leader Adam Walker has been arrested on suspicion of electoral fraud.
A Lancashire Constabulary spokesman said that a 47-year-old man from County Durham was arrested on Friday (12 August) on suspicion of electoral fraud and subsequently bailed.
The accusations are believed to relate to the far right party's campaign in Pendle's Marsden Ward in May's local elections.
In a statement on the party's website, the BNP said "Sadly, we've come to expect this kind of harassment whenever we come this close to winning council seats."
In May, police launched an investigation into Pendle Conservative allegations of postal fraud and voter intimidation by the BNP during the election campaign, the Lancashire Telegraph reported.
Tory Councillor Tommy Cooney beat BNP candidate John Rowe by 473 votes to 437 in a tightly-run contest.
Walker was elected party chairman in June 2015, after serving as acting chairman following the resignation of Nick Griffin in 2014. In 2013 Walker was struck off the teaching register for life, losing a subsequent appeal against then Justice Secretary Michael Gove.
He was initially handed a two-year ban by the National College for Teaching and Leadership after verbally abusing two boys and slashing their bike tyres with a knife in 2011.
The BNP's share of the vote collapsed by more than 99% in the 2015 general election, amid internal fighting and rising support from rival anti-immigration parties.