A hospital trust has been told it must improve following an inspection from England's chief inspector of hospitals.
The Care Quality Commission rated North West London Hospitals NHS Trust, which runs Northwick Park Hospital, as 'requires improvement' after an inspection earlier this month.
The commission found a shortage of staff was having an impact on care in some parts of the trust.
Maternity services were also identified as requiring improvement, and were rated as inadequate for responsiveness, as women could not always summon help needed.
The commission did find staff across the trust were caring and compassionate towards patients, and their families and friends.
There were several areas of the trust which were rated as outstanding, including the stroke unit and the short-term assessment, rehabilitation and reablement service (STARRS) which aims to mitigate pressure on A&E.
Chief Inspector of Hospitals Professor Sir Mike Richards said: "When we inspected the hospitals run by North West London Hospitals NHS Trust we saw that while staff were caring and compassionate, staff shortages made it difficult for them to meet people's individual needs.
"Particular attention needs to be paid here to the staffing issues identified and to improvements that need to be made to the patient environment.
"Ongoing improvements to maternity services also need to be sustained, and further changes be made at a much greater pace to ensure that women receive a service which is safe, caring, effective and responsive to their needs."
In response to the report, the trust's chief executive David McVittie said the report was a fair reflection.
He said: "It identifies where improvements are required and also recognises areas of good performance and outstanding practice.
"Importantly, the report confirms the care, commitment and compassion of our staff.
"A significant amount of work is already underway to improve safety and effectiveness of care in our maternity unit.
"Our A&E care will also be improved through the planned centralisation of services in North West London.
"We were pleased that the CQC inspectors identified a number of areas of outstanding service including our stroke unit and STARRS service.
"As a trust we aspire to provide the best possible care to all of our patients. We have a good understanding of the challenges that we face and were able to highlight these to the CQC at the start of their inspection.
"The work, to improve our services has already started. Some changes will happen fairly quickly others will take longer to bring about."