An Oxford University professor and government adviser on tackling extremism is facing new allegations ​including sexual misconduct with minors.

Prof Tariq Ramadan was accused of rape last month by a French feminist author. He has denied the allegation and said he will sue for libel.

He is now facing new accusations from four Swiss women who say he made sexual advances to them when they were studying under him as teenagers in Geneva.

One of the women told Tribune de Geneve newspaper Prof Ramadan made unsuccessful sexual advances to her when she was 14 years old.

Another alleged he had sexual relations with her in the back of his car when she was 15 years old.

The other two women said they were 18 when they had sexual relations with him, but accused him of abusing his position of power as their teacher.

Prof Ramadan was accused of rape by the French author Henda Ayari last month.

Since then two more women have accused him of rape. He has denied the accusations and filed a case for libel in the French courts.

In statements posted on Facebook, he claims he is being targeted by “a campaign of slander clearly orchestrated by my longtime adversaries” and says he has been advised by his lawyers not to comment further.