Dear [send to line manager],
As an employee I have a duty to report any concerns I have about the health and safety of my workplace and issues affecting the safety of our patients.
As my employer, under health and safety legislation, you have a duty of care towards your staff and the patients they care for and should take all reasonable steps to address these concerns.
With both of these points in mind, I am writing to raise the following concerns.
[Add detail as appropriate. You may wish to mention: On (X shift on X day) there were not enough nursing staff to deliver safe care; staff:patient ratio; staffing levels and the skill mix; number of patients and their acuity; availability of appropriate PPE; clear leadership or management; adverse events; and other ways you have tried to raise this concern].
As an [insert role title], I act at all times to deliver safe and effective care to patients and uphold high standards. I have done all I can but care is currently being compromised. Given the nature of my concerns, I am formally asking you to intervene in the interests of safe care.
I intend to share a copy of this letter with my trade union, the Royal College of Nursing.