Conservative Party chairman Lord Feldman is to stand as a witness in an investigation into allegations of bullying, sexual misconduct and blackmail involving former aide Mark Clarke. The barrister is one of 40 witnesses to be questioned by party officials in an inquiry led by a city law firm following the death of 21-year-old Conservative youth wing member Elliott Johnson.

Lord Feldman has faced increasing pressure to stand down from his post and yesterday (28 November) former chairman Grant Shapps, who has also been embroiled in the scandal, resigned from his position as international development minister. Johnson's father, Ray, has said the pair "need to stand down" in the past few days.

British Transport Police launched an investigation into claims of bullying after the discovery of Johnson's body by train tracks in Bedfordshire in September. Before his death he is said to have made complaints about bullying to the party about Clarke, who has since been expelled from the party for life, but says he did no wrong.

It is claimed Clarke – known as the "Tatler Tory" after he posed for the magazine – was sexually aggressive towards female activists, and blackmailed and bullied other members of the party. It has also emerged that Clarke had told MPs that he had been offered a safe seat in the 2020 general for his campaign work, implicating Shapps when he was still co-party chairman.

The party has insisted it has no records of written complaints despite a number of activists saying that they had reported Clarke for his conduct. Andrew Feldman, or Baron Feldman of Elstree, is involved in the scandal because he signed off Clarke's involvement in the Conservative election campaign – where he organised 'Road Trip' which bussed young Tories around the country.

Clifford Chance LLP has been instructed by the party to prepare a report to establish whether complaints were handled properly and to "identify any individuals who were at fault". Shapps said yesterday: "In the end, I signed that letter appointing Mark Clarke 'director of Road Trip' and I firmly believe that whatever the rights and wrongs of a serious case like this, responsibility should rest somewhere.

"Over the past few weeks – as individual allegations have come to light – I have come to the conclusion that the buck should stop with me."