The NHS and Army’s project to convert London’s ExCel into a 4,000-bed field hospital — a plan of unprecedented scale for this country — is grappling with major clinical and cultural tensions, as well as the huge logistical challenge, ahead of its official opening next week.

On Monday news leaked that military planners had visited the ExCel centre in east London to scope the prospect of building a field hospital there. The news blindsided even well-connected senior NHS figures, such was the crazy pace of events.

By Wednesday it was announced the facility would open next week. The NHS and Army are now forging ahead with what NHS England boss Sir Simon Stevens declared “a model of care never needed or seen before in this country”. NHSE said it would initially provide around 500 beds equipped with ventilators and oxygen and grow from there.

Senior figures told HSJ the NHS Nightingale would effectively be run as “an outpost” of Barts Heath Trust intensive care unit.

A management team was also being established. The full line-up has not been announced but HSJ understands University College London Hospitals Foundation Trust director Ben Morrin has been given a key role as workforce lead.

There are countless thorny issues for decision makers to tackle.

One major issue reported to HSJ is what one source familiar with developments described as a “clash” of cultures between the Army and NHS clinical leaders over clinical decision making.

Another senior NHS figure familiar with discussions told HSJ divergence of opinion was largely between on the one hand most NHS hospital medics and managers, and on the other hand military doctors with medics from NHS emergency departments.

They said: “The default of hospital medics and managers is to try to continue business as usual, and assume resources are infinite.

“The military and ED consultants [have] a completely different mode of thinking — you accept that you cannot do everything for everyone and target treatment on those most able to survive and with a maximum quality of life.”

The source added: “The danger at the ExCel is they will try to run it as an ICU [but] what [could] happen is undifferentiated patients start being delivered there. [This means] they [may need to be] prepared to act as an emergency department and deal with the triage process.”

An even more stark decision was described by another senior figure about what mix of patients should be sent to ExCel. Much “clinical opinion”, one source said, was of the view that “sick patients should be in [normal] hospitals with all necessary kit around” while “step downs”, ie those in recovery, or “people at ceiling of care” — those unlikely to recover and where no further clinical intervention is appropriate — “could go to Excel”. The source argued the latter “wouldn’t look great - ie ExCel full of the dying”.

Some senior non-military clinicians are welcoming the leadership of the Army.

One London clinician with experience of working alongside the military said: “I would rather that the military run this. There are a number of well seasoned military doctors working in the NHS, all with experience of working for long periods in resource-limited environments, some of whom are high-regarded intensivists.

“I would feel reassured pitching up and seeing them giving the orders.”

This doctor agreed, however, that system leaders needed to quickly clarify whether the site would be exclusively an intensive care centre, or a covid-19 centre which would include intensive care.

“The logistics of these two things are entirely different. The former has less risk of misdiagnoses but has increased problems around transfer of critically ill patients. The latter increases the risk of misdiagnoses unless a lot of equipment, such as CT scanners, are moved to the ExCel.”

The source who had raised concerns over the clash of cultures between many NHS clinicians and the military also raised concerns about the “frightening” prospect of “thousands of staff, some of whom have no experience of the machines/IT etc…The military approach is to keep things very, very simple, whereas the ICU philosophy encourages the exploration of rabbit holes”.

And, of course, all this must be organised in an environment where it is accepted that safe staffing ratios have to be significantly diluted, which of course will raise its own significant safety risks.

As HSJ revealed on Monday unions have agreed to plans to increase ICU nurse-to-patient safe staffing ratios from 1:1 to 1:6 (with other staff in support) as the NHS tries to spread the capacity it has as far and wide as possible.

In normal times, this would have been inconceivable, but there is a grim acceptance there’s no alternative.

There is also the issue the Nightingale will suck staff away from other hospitals. The call has gone out to surrounding trusts to identify staff they would be prepared to send to the Excel centre, as revealed by HSJ.

Suffice to say the charge of “robbing Peter to pay Paul” was levied at system leaders. But, again, there is not a plentiful supply of alternatives.

On top of these clinical dilemmas, establishing the physical logistics, facilities and infrastructure, not to mention technology, are as huge as they are complicated.

Officially, the government has announced the Nightingale will open “next week”, and sources in the capital had been told it could be as early as Sunday or Monday. HSJ has heard the opening is likely to be pushed back to Wednesday, following issues with installing oxygen containers — a small indication of the enormity of the project.