A former Ukip activist who is partnering with Nigel Farage in launching a new pro-Brexit political party has argued crime and fatherlessness among black men are due to high testosterone levels, and suggested their lower academic achievement could have a biological basis.

Catherine Blaiklock has also expressed concern about “Muslim enclaves” and said food banks should be abolished as they create a “dependent, obese population”.

The former parliamentary candidate and economics spokeswoman for Ukip, who has also argued too many women train as doctors, confirmed at the weekend she had applied to register Farage’s new party last month.

Farage, a former Ukip leader, has vowed to contest any general, local or European elections with the new party if he believes Brexit is being thwarted.

Blaiklock quit Ukip in December, shortly after Farage did the same. They were among a series of high-profile members to leave after the current leader, Gerard Batten, appointed the anti-Islam activist Tommy Robinson as an adviser, amid wider concerns about the direction of the party.

Soon after Blaiklock announced she had registered the party with the Electoral Commission, her Twitter feed appeared to be deleted, as were some posts from her personal blog.

One of the deleted posts, titled “Baby mamas, gangs and testosterone”, argued biological reasons could be behind gang violence and family breakdown among men of African-Caribbean origin in the UK and the US.

“I always joke that that black American men go crazy in their teens and 20s because of all their excess testosterone, have lots of babies, sex, violence, drugs, sport and music and then at 35, when their testosterone reduces to near the levels of white men, all settle down and become washing-machine repairmen. I may not be so far from the truth,” she wrote.

“We do not like to talk about biology when related to race, but what is good for winning 100m races might not be great for passing A-level maths exams.”

In another post, which has not been deleted, Blaiklock writes about her discomfort when encountering a woman wearing a full-face veil and expresses worry about the extent of Muslim immigration.

Using a US example, she describes two cities near Detroit “that have become almost total Muslim enclaves”. The cities, Hamtramck and Dearborn, have significant Muslim populations but are otherwise diverse.

In a post on the Conservative Woman website in January titled “Hungry? Let them eat spuds!” Blaiklock said food poverty was a myth and food banks should stop their activities as “they are creating a dependent, obese population”.

In another post on the same website, she argues the NHS wastes large amounts of money by employing female doctors who then have children. To stop this, the NHS needs to “tie them into contracts, as with the army”, she suggests.

Blaiklock said she had taken down her Twitter account “because I have no time right now to monitor it”.

She added: “I have been happily married to a Jamaican man for six years, so anyone implying I am racist is revealing more about themselves than me.”

A representative for Farage was contacted for comment.