A party spokesman previously confirmed Braine's desire to step down after his statement that the national executive had tried to suspend him amid a struggle for control of the party.
"I had believed that Ukip was a highly democratic party, but I have not been able to stop political interference in Ukip ballots. I cannot therefore stand publicly for Ukip with a clear conscience", Braine said in a resignation letter, as quoted by The Guardian newspaper.
He also added that his efforts to lead the party were 'met with pre-emptive opposition' from senior figures, including chairman Kirstan Herriot.
"I did not join Ukip in order to waste time on internal conflict, but I have found myself powerless to prevent a purge of good members from the party," Braine wrote.
The row happened amid a wider controversy over the future of the party following Braine’s election in August. Herriot and some other national executive members hoped that the new leader would shift the focus on anti-Islam policies, hailed by the previous head of the party, Gerard Batten. However, Braine continued to pursue the same policies. As a result, the national executive tried to prevent Batten-associated members from standing in elections to the body.
Amid the recent developments, Braine’s tenure was featured by a slump in membership. UKIP has been hit by crises since Nigel Farage's resignation in 2016, followed by a series of short-lived leaders. It is now polling at less than 1 percent as supplanted by Farage’s new Brexit party.
