Monitor has launched an investigation into Bradford Teaching Hospitals Foundation Trust, following concerns raised by the Care Quality Commission about accident and emergency staffing levels.

The CQC identified problems with A&E staffing at the trust’s Bradford Royal Infirmary site during an unannounced inspection carried out in September and October last year. Its concerns were sufficiently serious for it to serve the hospital with a formal warning notice.

In its inspection report, the CQC said staffing levels within the department were “significantly low, particularly in relation to nursing staff and senior medical cover; especially midnight and throughout the night”.

The department was sometimes “significantly overcrowded”, meaning “people’s privacy and dignity were regularly compromised”, and triage and treatment were on occasion subject to unsafe delays.

When looking at the duty rota for nursing staff over a four-week period, the inspectors found there were shortfalls every day. In one week 18 shifts were not covered by a registered nurse and nine shifts not covered by a healthcare assistant.

Similarly, when they looked at the medical rota for 21 days, they found that on 17 days there was only one senior grade doctor on duty from midnight until 8am, which the inspectors thought could compromise care.

In light of the CQC’s findings, Monitor is investigating the trust to see if they are “symptomatic of wider issues with how the trust is run”.

In a statement the trust said it acknowledged the areas for improvement and took the CQC’s concerns “extremely seriously”.

It added: “Robust action plans have been in place since the CQC inspection in October and we took a number of immediate steps to significantly increase staffing levels.

“Substantial investment in staff and a sustained recruitment drive have helped us fill vacant and newly established posts and we will continue this process throughout the next few months.”