A recruitment drive aimed at turning around the performance of the ambulance trust that serves Hertfordshire could take up to two years to take effect.
The chief executive the East of England Ambulance Service met with MPs on Tuesday to discuss how improvements to the service were moving along.
Last month the Care Quality Commission released a report that stated the trust was still missing its target response times for life-threatening cases.
Dr Anthony Marsh from the trust said although 400 student paramedics had been recruited already, it was likely to take another two years before they would make an impact on the service.
He added: "It was incredibly beneficial to meet with MPs today, to hear their views about the service in their area and to assure them that progress and actions are already underway.
"The MPs were very supportive of the trust and the actions we are taking and it is reassuring to know we are all working together to turn this into a high performing ambulance service."
The meetings mark six weeks of being at the helm of the East of England Ambulance Service NHS Trust.
Dr Marsh added: "My immediate priority is to reduce long ambulance delays.
"One of the main reasons for the delays is that we don't have enough paramedics so I’ve launched a programme to recruit 400 student paramedics.
"We’re staggered to have received more than 2,500 applications already - and recruitment is still on-going."
At the end of January the trust met all but two of the Care Quality Commission’s seven safety standards, but needed to improve its response times and a shortfall of hundreds of paramedics.
Although the trust consistently met performance targets in relation to its less urgent calls, its performance in urgent calls was still below expectations.
Ambulance services are required to respond to at least 75 per cent of life-threatening calls within eight minutes, and 95 per cent of all calls within 19 minutes.
As well as bringing in new staff, Dr Marsh has been focusing on opening up career opportunities for frontline staff, allowing emergency care assistants to become emergency medical technicians, and for them to become paramedics.
Dr Marsh said: "Turning around this ambulance service is going to take time but the actions we are taking right now will better support our staff to improve services to patients."