London-wide specialist ambulance service for critically-ill patients

A specialist ambulance service for transporting critically-ill patients between hospitals across London starts tomorrow (1 April 2023). This will be called the Adult Critical Care Emergency Support Service (ACCESS) and will replace our existing north west London transfer service.

ACCESS is a partnership of Imperial College Healthcare, Barts Health, St George’s NHS hospital trusts, and the London Ambulance Service (LAS). It will see a fleet of specialist ambulances on standby in the capital so that the sickest patients who need expertly-tailored care at a specialist hospital (such as a cardiac centre or a hyper-acute stroke unit) can be safely moved between local hospitals and specialist centres.   

The four vehicles will carry extra equipment, including ventilators and specialist monitors, and be staffed by expert clinicians so they effectively act as a network of mobile intensive care units. The ambulance fleet will be based at sites across London and together are expected to transport about 2,000 patients a year.

The north west London hub will be at Imperial College Healthcare's Hammersmith Hospital. The new service will not affect our existing emergency pathways where transfer is extremely time critical, such as Major trauma, stroke, aortic dissection and heart attacks. Transfers for Extra Corporeal Membrane Oxygenation (ECMO) will continue to be handled by existing ECMO services.


The new pan-London service is a collaboration modelled on the successful North East London Critical Care Transfer And Retrieval (NECCTAR) service, with input from the other partners on best practice including in our own experience of hosting the north west London transfer service. 

NECCTAR earned its reputation during the Covid-19 pandemic for the safe long-range transfer of adults with complex needs, particularly respiratory patients on ventilators. Crews travelled as far away as Cardiff and Newcastle, although most transfers are between London hospitals. For example, taking critically-ill heart patients to St Bartholomew’s for cardiac surgery, to St George’s for care following a brain injury or to Hammersmith Hospital for specialist kidney care.

Clinicians will staff the modified ambulances under consultant supervision. LAS will supply call handling, crews and vehicles, with other support functions carried out by partners in South West and North West London. South East and North Central London will also benefit from this scaled up service.

Clinicians will call LAS on a dedicated phone line, staffed by experienced call handlers at the Service’s emergency control centre, who will dispatch vehicles once agreed by the ACCESS duty consultant.  

David O’Callaghan, Critical care lead for north west London and site medical director for Charing Cross at Imperial College Healthcare, said: “North west London has a long history of education and training in transferring critically unwell patients. This knowledge helped the north west London transfer service, hosted initially by Royal Brompton and Harefield hospitals and latterly by Imperial College Healthcare, move large numbers of patients around the capital during and after the Covid-19 pandemic, collaboratively and with participation of trained staff from across the sector.  

“We're excited to be part of this new London-wide transfer service and look forward to sharing what we've learnt about transfers with our partners.”

Dr Jonathon Dean, operations director for NECCTAR, said: “No hospital houses every medical specialty or has unlimited capacity, and our collaboration will ensure that all London patients irrespective of postcode have access to the same high quality of critical care. 

“Moving critically unwell patients from a place of relative safety like intensive care is an inherently risky activity and requires both highly trained personnel and specially-designed equipment. 

“We have retrieved patients with failing hearts, moved others with internal bleeding, become quite efficient at time-critical trauma transfers, taken patients with temporary fragile cardiac implants to Papworth for transplants, become quite skilled at bariatric transfers for obese patients, and successfully completed a large number of long-range transfers which carry unique risks.” 

Daniel Elkeles, Chief executive at London Ambulance Service, said: “Every year, we respond to millions of 999 and 111 calls and are proud to be the capital’s emergency and urgent care responders. Beyond that initial response to people in their hour of need, we are delighted to play a vital role in the safe transfer of critically-ill patients if and when they need it and are pleased to help expand this service across the capital. 

“These ambulances have been modified to carry more specialist equipment, such as additional monitors and ventilators, and by working in partnership with our NHS colleagues in London we can ensure that our sickest patients can get the best possible care.”

Dr James Marsh, Group deputy chief executive officer for St George’s, Epsom and St Helier University Hospitals and Health Group, said:“ Critically unwell patients always need readily accessible specialist treatment. Our exciting new collaboration means more seriously ill and injured Londoners will receive the outstanding care they need from our teams of highly-talented clinicians, no matter where they live in the capital. We're very proud of the work we do here at St George's, and hope this fantastic new service means even more people can benefit from our world-class workforce and facilities.”