A shadow minister has stepped down from her post after being accused of trying to isolate a parliamentary worker who had made allegations of sexual harassment against a left-leaning Labour MP. Kate Hollern, a shadow communities minister and former aide to Jeremy Corbyn, attempted to dissuade the Conservative MP Andrew Bridgen from offering support to the staff member known as Ms A, an employment tribunal was told on Wednesday. Bridgen’s claims emerged at the tribunal in central London where Mike Hill, the former MP for Hartlepool, faces accusations from Ms A of sexual harassment and victimisation. Hill vehemently denies the allegations. After being approached by the Guardian, Hollern, the MP for Blackburn, who was Corbyn’s parliamentary private secretary at the time of the conversation, apologised for speaking to Bridgen about Ms A, but said it was never her intention to undermine any support received by the complainant. A Labour source confirmed that she has stepped down from her post. In a witness statement, Bridgen said he had met Ms A on several occasions in parliament in 2018 and 2019 and she had told him about Hill’s alleged sexual harassment. Bridgen said he had advised her to speak to lawyers, but she told him she did not want to take action because she feared losing her job, the hearing was told. Bridgen claimed that on 21 May 2019, he was approached by Hollern on the terrace of the House of Commons, and asked to move away from fellow MPs. He claimed she said: “Everyone is saying in the Labour party that you are having an affair with [Ms A] and if I were you I would keep away from her, because you have a wife and baby and you would not want to lose them if it got in the papers.” Asked about Hollern’s alleged comments before the tribunal on 12 May, Bridgen said: “I believe that it was [said] to isolate the applicant from any help and support and I thought that was pretty appalling actually … I thought it was quite malicious and I don’t respond well to intimidation like that, I can assure you.” Ms A said in her witness statement that she had confided in Hollern, a close colleague of Hill, about Hill’s alleged sexual harassment. After confiding in Hollern, Ms A said, she was approached by the Blackburn MP on the terrace in parliament and advised that few complaints against MPs were successful. “Ms Hollern said that many people in parliament had put in complaints in the past of sexual harassment and nothing was ever done about it, which deterred me from seeking further advice at that time,” Ms A wrote. Hill resigned as a Labour MP in March, resulting in Thursday’s byelection in Hartlepool and a victory for the Conservatives. On Tuesday, the tribunal was told that Hill wrote to Ms A saying he craved her body, and climbed uninvited into her bed on two occasions. She alleged he rubbed his erect penis against her buttocks and fondled her breasts, despite promises not to pursue her. She also claimed he harassed her in parliament. Ms A claimed he sent her messages saying “I love you”, adding that he “wanted a sexual relationship”. Under cross-examination on Wednesday, Ms A rejected suggestions that her claims against Hill were untrue. Tom Perry, counsel for Hill, questioned her on the allegation that he had rubbed his erect penis against her bottom, putting it to her that it “didn’t happen”. An often tearful Ms A described the alleged experience to the tribunal, which she said later left her “shaking”. During cross-examination at a virtual hearing, Ms A said she had previously received a £40,000 out-of-court settlement from a former employer. Ms A said she was refused a pay rise and eventually lost her job after declining Hill’s advances. Her complaint about alleged sexual assault, harassment and victimisation was lodged last year with Labour and also with parliament’s Independent Complaints and Grievance Scheme (ICGS). Hill was suspended from the party. In response to Bridgen’s submission and testimony, Hollern told the Guardian it was never her intention to undermine any support offered to Ms A and apologised if she had done so. “I am absolutely clear that any complaint of sexual harassment should be treated extremely seriously. It was never my intention to undermine the support the complainant was receiving, which I was unaware of at the time. If that is what Mr Bridgen was led to believe, I apologise for my error in judgment in having the conversation,” she said. The tribunal continues.