A rightwing Tory fringe group whose material discusses mass deportations to Africa and links immigration with rape has been addressed by senior Conservatives Owen Paterson and Liam Fox in the House of Commons in recent weeks.

The two former cabinet ministers spoke at separate meetings of the London Swinton Circle in October and November in spite of previous controversies about the Conservative party’s association with the group, set up in the 1960s by admirers of Enoch Powell. The backbencher Christopher Chope is also understood to have spoken at one of the circle’s gatherings.

The London Swinton Circle – separate from a rival faction which claims to be the true Swinton Circle – states that some of its purposes are national sovereignty, maintenance of the union, qualified immigration and the restoration of capital punishment. However, its online newsletter also contains a series of controversial statements about immigrants, rape, women and gay marriage, among other topics.

One article from February 2014 about David Cameron’s immigration bill examines the possibility of a new version of the repatriation of ex-slaves from Britain to Sierra Leone in 1787.

It states: “Whilst only a few blacks were actually transported, the episode serves as a precedent. As the principle of the mass movement of people is accepted by all the mainstream parties, then would it not be difficult to argue against the mass movement of people from Britain to say some part of Africa?”

Another piece from August 2014 about “interracial rape” in the Rotherham child abuse scandal states: “Rape had became a business for the immigrants – something to think about next time you hear a politician extolling the benefits of an immigrant-based economy.”

A separate article defends Emma West, who was convicted of racially aggravated harassment on a Croydon tram. The article objects to “foreigners in our schools, in our hospitals, in our prisons, in our benefit centres, in our sports, in our media, and in our political structure” and accuses any black British citizens of being a “colonist” seeking to “appropriate even our identity”.

Aside from immigration, one article from spring 2014 questions whether the earthquake in New Zealand was a warning against gay marriage.

Another from May 2012 argues that “without a husband a woman is but a sexual object to be shared around”.

Last night, the Labour MP Sheila Gilmore called on the Conservative party to explain why it is allowing some of its most influential rightwingers to associate with a group “pushing such vile views”.

“These Conservative MPs must immediately explain their actions and their associations with this group and the Conservative Party should explain why it is content for this association to continue,” she said.

Paterson is seen by some on the Tory right as a potential leadership contender, who has been promoting his hardline Eurosceptic views in recent weeks.

Only Fox responded to requests for comment when the three MPs were asked about their involvement with the London Swinton Circle, whether they were previously aware of some of the group’s newsletters and if they endorsed any of its aims.

His office said: “Dr Fox was not aware of any of the views that you mention. He accepts a wide range of speaking engagements and is willing to make the Conservative case to many different groups who may not agree with Conservative policy. This is part of the democratic process.”

The controversy comes after Jacob Rees-Mogg, a Conservative backbencher, apologised last year for speaking at a meeting of the rightwing Traditional Britain Group, which had subsequently suggested Doreen Lawrence and other black people should be “requested to return to their natural homelands”.

It also follows criticism of Neil Hamilton, the Ukip deputy chairman, this week for having been pictured in front of the national flag of apartheid-era South Africa at a meeting of the Springbok Club, which has ties to the other faction of the Swinton Circle. The picture was taken in 1998 and the Springbok Club says it is now a “socially orientated home for expatriate Southern Africans”, not a political organisation.

There is a history of controversy about Conservative involvement in the Swinton Circle that erupted in the early 2000s when the party’s then leader, Iain Duncan Smith, cut ties with the Monday Club over allegations about its racism. In 2001, a Conservative party review of the fringe groups associated with the Tories found they “did not think there is a problem with the Swinton Circle”, although at least one of its MPs pulled out of a speaking event following publicity about its views.

The Conservative party was asked whether it still has no problem with the London Swinton Circle, but declined to comment on the grounds that it is up to MPs to justify to whom they speak.

A London Swinton Circle organiser, Allan Robertson, told the Guardian that the meetings with Fox, Chope and Paterson were under the Chatham House rule so he could not reveal what was discussed.

He strongly rejected the idea that the London Swinton Circle endorses repatriation or thinks that only white people can be British, but said he could not remember what had been published in some of the group’s newsletters.

“We have too much immigration in the last 15 years and it has become very difficult for the country to sustain. If the Conservatives come back to power next year, they will be able to do more,” he said.