Liham mula kay Dr Frank Atherton (Chief Medical Officer para sa Wales), Dr Catherine Calderwood (Chief Medical Officer para sa Scotland), Dr Michael McBride (Chief Medical Officer para sa Northern Ireland), Propesor Chris Whitty (Chief Medical Officer para sa England) at Professor Stephen Powis (National Medical Director, NHS England at NHS Improvement) sa Mga Kasamahan na pinamagatang Novel Coronavirus: Clinical Trials, walang petsa.