The UKIP party chairman in the constituency where leader Nigel Farage hopes to become an MP has said he "deeply regretted" his past membership of the National Front.
Martyn Heale, now a county councillor for UKIP in Kent, was a member of the far right organisation in the 1970s, but he insists he is not racist.
He also told the BBC it was "really depressing" to be reminded of his past.
Mr Farage confirmed he would seek selection in Thanet South in August.
Mr Heale has been a member of UKIP for more than a decade, and prior to that was a Conservative activist for almost 20 years.
He acknowledged that in the late 70s he was an active member of the National Front for more than a year.
Councillor Heale did not want to do a broadcast interview, but told BBC political correspondent Chris Mason: "I obviously regret what I did."
"It is really depressing," he added, to be reminded of his past.
Mr Heale acted as Mr Farage's election agent in 2005 when the UKIP leader ran, unsuccessfully, for Parliament in Thanet South.
A spokesman for UKIP said Mr Heale had been a party member for several years before the ban on former members of far right organisations was brought in.
To expel him "would be contrary to natural justice", he said.
Mr Farage, who was born in Kent, has represented south-east England in the European Parliament since 1999.
South Thanet is currently held by the Conservative MP Laura Sandys, who was elected in 2010 and has a majority of 7,617.
She is standing down and the Tories have chosen a founding member of UKIP and former leader of the party, Craig MacKinlay, as their candidate.