The region’s under-fire ambulance service has made “significant improvements”, but is still failing patients with slow response times, according to health inspectors.

The Care Quality Commission (CQC) found the East of England Ambulance Service NHS Trust was failing in two key areas.

Inspectors from the watchdog carried out an unannounced inspection of the under-performing organisation in December and found that the service was not hitting standards because of slow response times and a lack of qualified paramedics.

The chief executive of the ambulance trust, Anthony Marsh, pledged to make further improvements after the CQC said the service was not hitting staffing standards and the level of care and welfare for people who use services was not good enough.

The ambulance trust has been given a month to put together an action plan to address performance problems after not hitting any response targets for the whole of 2012/13 and was forecasted to underachieve in 2013/14.

The regulator added that it had decided against enforcement action because of efforts to address staffing and performance problems.

In its report published last week, the CQC said that the trust had made “significant improvements” since its last inspection in January and February 2013. Staff sickness absence rates have reduced and complaints relating to ambulance delays had decreased, as had the number of serious incidents experienced by the trust.

The report added: “However, the trust had not seen the improvement needed in some areas such as its ambulance response times to life-threatening 999 calls. There continued to be large variations in response time performance across different regions of the trust and there remained problems with getting people who had suffered a stroke to a specialist centre within 60 minutes.

“Ambulance delays at hospitals, although improving in some areas, still did not meet the required level of performance and the trust had incurred fines from its commissioners as a result.”

The CQC inspectors said there were big variations in performance across the six counties the service covers, with Luton and Cambridge exceeding targets and parts of Norfolk and Essex consistently failing to hit targets.

The inspectors also noted that the trust was meeting standards in the areas of safety, availability and suitability of equipment, requirements relating to workers, supporting workers, complaints and assessing and monitoring the quality of service provision.

The new chief executive of the East of England Ambulance Service was keen to focus on the positives of the latest CQC report.

Anthony Marsh said: “I welcome this report as it shows everyone where we are – the improvements we have made – and confirms that the changes we are making will tackle the other areas that need improvement, although this will take time.

“We have started recruiting 400 student paramedics and I am delighted that we have had in excess of 1,000 applications in the first week. In addition, we will be looking to recruit more graduate paramedics and provide additional training for existing staff.

“This, along with other actions we have put in place such as our Hospital Liaison Ambulance Officer schemes to help speed up patient handovers at hospitals, will improve patient care, reduce ambulance delays and be beneficial for staff.

“Although I have only been with the trust for under a month I can clearly see the determination of everyone throughout the service to succeed and provide the type of service that we all want to see.”