A hospital boss who blamed staff for a Covid-19 outbreak that led to a partial shutdown of its A&E unit has resigned. Hillingdon hospital in London announced on Friday that Sarah Tedford was standing down as chief executive “for family reasons”. There was speculation that colleagues had lost confidence in her leadership after she accused staff of contributing to the spread of the virus by not wearing masks or practising social distancing. The Guardian disclosed last month that Tedford had appeared in an image posted on the hospital’s Facebook page without a mask while sitting beside a sign that highlighted Hilingdon’s rule that all staff should cover their faces while on the premises. Tedford, who joined the NHS as a student nurse in 1985, left the hospital “with immediate effect” on Friday, said the chair of its board, Sir Amyas Morse. Tedford said the pressures involved in responding to the coronavirus pandemic had “caused me to reflect about working so far away from my family”. Public Health England, NHS England and Hillingdon council are investigating the outbreak at the hospital, which serves Boris Johnson’s constituency. The inquiry has heard that 70 nurses had to go into quarantine after some failed to wear masks or stay 2 metres apart at a training event in the hospital’s education centre. That led to one nurse infecting 16 others, who in turn passed it on further. The Care Quality Commission, the NHS care regulator, undertook what Hillingdon described as “a focused inspection” of the hospital this month. CQC inspectors told the hospital to make immediate improvements to protect staff and patient safety, including introducing a daily check to identify safety or clinical problems and tackle them. The hospital’s deputy chief executive, Jason Seez, who has replaced Tedford on an interim basis, said in an email to staff on Thursday that improvements to safety “could be measures as simple as making sure everyone wears a mask and maintains social distancing”.