The letter comes after an independent report from Dame Laura Cox which warned of a culture of “deference and silence” that “actively sought to cover up abusive conduct” and gave no protection to those reporting bullying or sexual harassment.

In the letter Garry Graham stressed the need for effective leadership to put the well being of staff ahead of political interests or personal agendas.

The letter said:

"Our members are proud of the work that they do- but feel deeply let down by the institution they work for and contribute so much to.

"Most MPs are honourable people and treat our members with the dignity and respect that they deserve.

"However there are deep seated cultural and systemic matters which need to be addressed if the intolerable behaviours some of our members have been subject to are to be exposed and eradicated."

Prospect will share all responses with members.