The following letter has been sent to all MPs on behalf of the following group of MPs.
Stella Creasy - Labour and Cooperative MP for Walthamstow
Sarah Wollaston- Conservative MP for Totnes
Jo Swinson - Liberal Democrat MP for East Dunbartonshire
Diana Johnson- Labour MP for Kingston Upon Hull North
Liz Saville Roberts- Plaid Cymru MP for Dwyfor Meirionnydd
Caroline Lucas- Green MP for Brighton Pavillion