Reform UK’s parliamentary candidate in Kemi Badenoch’s constituency has resigned from the party after it emerged he previously urged people to vote for the BNP.

Grant StClair-Armstrong, who is standing in North West Essex, also used a blog to post jokes using racial slurs and made a joke about “female hormones”, according to the Times.

He told BBC News he had “never supported the BNP” and “bitterly” regretted the comments.

Mr StClair-Armstrong will still appear on the ballot paper as the Reform UK candidate because the deadline for nominations has passed. But if he is elected he would stand as an independent.

The Times reported that, in 2010, the candidate had written: “I could weep now, every time I pick up a British newspaper and read the latest about the state of the UK. No doubt, Enoch Powell would be doing the same if he was alive. My solution … vote BNP!”

Mr StClair-Armstrong told BBC News he posted the comment some time between 2004 and 2007 and he was an “angry man” at the time.

“I have never supported the BNP. I think they are a disgusting organisation,” he said.

Asked whether he had chosen to resign, he said the party had forced him to.

“To be honest, I wouldn’t have stepped down. I would have let the people decide,” he said.

According to the Times, on a blog he called the “Joli Triste” Mr StClair-Armstrong wrote about the Scottish politician, Kenny MacAskill, wishing serious illness on them.

On the Chilcot inquiry into the Iraq war, he wrote: “The simple solution is to extradite Blair … [and] the odious Alistair Campbell to a country that routinely indulges in torture and execution”.

Speaking on Sunday, he said: “I bitterly regret all of those comments made many years ago and I am just sorry that some people deemed it necessary to hunt for them when I am not the person I was then.”

A spokesperson for Reform UK said: “Mr St Clair-Armstrong has tendered his resignation as a member of Reform UK due to the revelation of unacceptable historic social media comments and we have accepted his resignation.”

The list of candidates standing in North West Essex:

• Kemi Badenoch – Conservative
• Erik Bonino – Independent
• Edward Gildea – Green
• Andrew Green – Independent
• Niko Omilana – Independent
• Smita Rajesh – Liberal Democrats
• Grant StClair-Armstrong – Reform UK
• Issy White – Labour