Labor Party deputy leader Tom Watson was accused of "transforming" the party's secretary general, Jennie Formby, while she was undergoing breast cancer treatment.
Watson had written to Formby after a BBC Panorama program on anti-semitism at work. He asked him to publish the party's submission to the Commission for Equality and Human Rights (EHRC), which investigates allegations relating to work.
Watson also argued that she had suppressed emails relating to cases, which Formby denies.
Responding to Watson, Formby says "very disappointed". He had criticized the party's response to anti-Semitism and accused it of abusing its position.
"At all levels, the party has always shown that it recognizes the vital importance of the fight against anti-Semitism, but you constantly abuse your considerable platform to denigrate any progress made and anyone involved in this process." , she said.
"Acknowledging my reputation and attacking me publicly when you know I am undergoing chemotherapy and unable to respond to the media is another example of the inappropriate way in which you choose to discuss this issue."
The Chancellor of the Shadow, John McDonnell, one of the main allies of the leader of the Labor Party, Jeremy Corbyn, also attacked Watson. According to him, this "goes beyond the understanding", the letter was sent "when he knows that she is undergoing chemotherapy".
"I just do not understand why the deputy head of the Labor Party uses the media to request information from the general secretary of the @JennieGenSec movement, which has already been offered to him."
The spinoffs of the program continue to lead to heavy cuts in the party.
According to Watson, a document produced for the European Commission's investigation of human rights should be made public, as "only sunlight can now disinfect the work of anti-Semitism".