The husband of a Liberal Democrat MP has apologised after accusing Labour shadow equalities minister Dawn Butler of lying about her experiences of racism.
Steve Wilson, who is married to Angela Smith and is a member of her staff, has been accused of "trolling" Ms Butler after she wrote an article in the Metro newspaper as part of Black History Month.
Ms Butler shared an experience where she was told by an MP that the lift they were sharing was not "for cleaners", which she saw as an example of "blatant racism".
Mr Wilson subsequently accused the Labour MP of lying, and wrote in a tweet: "Sorry but this just not true. Stories like this don't do anyone any justice and anyone propagating then should stop it."
He has since deleted his tweet and his account.
When asked by Sky News if he had any further comment, Mr Wilson said: "There is normal procedure for this sort of thing… I've apologised… I've said what I have to say."
Dawn Butler has now written to Lib Dem leader Jo Swinson about his remarks, and said: "This isn't a 'story' or a lie.
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"This is race discrimination in the workplace; it is experienced by black, Asian and ethnic minority people in workplaces across our country on a daily basis and we need to stamp it out.
"White men denying our lived experiences and accusing those of us who do speak out about it of lying, not only legitimises, but it actively promotes racism."
In her letter, Ms Butler went further, asking Ms Swinson to assess whether there was a "particular problem" in Angela Smith's office which needed to addressing through diversity training.
Ms Butler said she had referred the incident to the House of Commons authorities to see whether it had breached the parliamentary staff code.
The Liberal Democrats said that they would not be making any further comment, instead offering Mr Wilson's apology.
"I apologise for the offence I have caused. We must all take responsibility for condemning racism and prejudice in all its forms, in order to stamp it out from our society," he said.