How will the NHS cope this winter?

The headlines may be dominated by Washington politics and the Brexit debate, but NHS managers are focusing on one issue above others - the winter and what it will mean for already stretched services.

Temperatures have dropped this week, and the Met Office has warned of an increased risk of cold snaps between now and Christmas.

That has certainly been concentrating minds in the upper reaches of the NHS.

There is nothing new about planning for winter in the health service.

Ministers and NHS leaders are always apprehensive at this time of year.

Mild winters in recent years have helped the system muddle through, although there were intense strains in late 2014 and early 2015.

But, as is well known, it only takes a stretch of cold weather and a prolonged bout of flu for hospitals to struggle.

In these circumstances, the service's resilience can be severely tested.

Patient demand has kept on growing.

The latest NHS England figures, external showed attendances at accident and emergency units and emergency admissions up nearly 4% over 12 months.

Most worrying for the service, delayed transfers of care (measuring patients stuck in hospital beds because of problems with the next stage of social or health care) were up more than a quarter over a year.

The system is already close to full capacity before winter has begun to bite.

Numbers arriving at A&E are high throughout the year rather than peaking in the winter.

The big problem for the service comes in late December and early January, when health care in the community tends to shut down for the seasonal holiday.

Hospitals come under even greater strain than usual, and that is a serious worry for NHS chiefs.

The Health Secretary, Jeremy Hunt, acknowledged on the BBC's Andrew Marr Show that this winter could be "very challenging".

I understand that even greater efforts are being made this year to try to relieve the pressure on hospitals.

Regional A&E delivery boards have been set up to bring together trust managers, GPs and social care leaders.

Their brief is to try to "de-risk" the situation.

That could involve GP practices getting more doctors working over bank holidays and keeping surgeries open.

Hospitals will be encouraged to plan leave allocations to ensure enough doctors are available for non-urgent care.

Social care managers will be expected to keep as many services open as possible, including home visits.

The Cabinet Office is once again closely involved in monitoring the resilience of the system.

Weekly meetings at the Department of Health, bringing together NHS leaders and ministers to review the performance of hospitals and local authorities will take place as usual.

Micromanagement it may be, but nobody in Whitehall wants to take chances.

The Welsh government has allocated £50m to NHS Wales to help deal with increased demand over the winter.

People with minor ailments, coughs and colds will be encouraged to talk to a community pharmacist before trying to see a doctor.

The Scottish government will soon announce its winter plans, but a representative said: "Our health and care services are well placed to cope with the additional demands of winter - including record funding and staffing, plus joined up health and social care."

The winter season is the immediate challenge, but the underlying problems remain.

The three think tanks, Nuffield Trust, the King's Fund and the Health Foundation, have published a stark warning about what they call the "critical" state of social care and what that means for the NHS.

Reductions in social care funding in England and hence the availability of accessible care, they argue, have imposed "significant human and financial costs on older people, their families and carers". This in turn has left more people "stranded in hospital".

They have called for a financial bailout of social care in the Chancellor's Autumn Statement.

The Department of Health says from next year extra funding for social care in England will start coming on stream.

Demand growth has outstripped health funding increases for some time.

The NHS has tried to keep up. Whether it can do so over a cold winter is anyone's guess.

Contingency plans are being made, but in Whitehall they can only sit, wait and hope.