Fears the NHS could be facing one of its toughest winters are rising after the flu season began early this year.

The NHS has issued a ‘flu jab SOS' with cases already triple what they were this time last year.

Speaking at The King's Fund annual conference yesterday, NHS England chief executive Sir Jim Mackey, said: ‘There's no doubt this winter will be one of the toughest our staff have ever faced.

‘Since stepping into this role, the thought of a long, drawn-out flu season has kept me awake at night. And, unfortunately, it looks like that fear is becoming reality.

‘Australia has just endured its worst flu season on record — over 410,000 cases — and all the signs suggest the NHS will face similar challenges in the months ahead. From December through to March, our hospitals will be at capacity.'

NHSE said it is making 2.4m flu vaccinations available for the vulnerable next week.

Over 13m flu vaccines have already been rolled out with three in five of all care home residents protected (59.4%).

However, only a third of eligible two- and three-year-olds have been covered despite the NHS making it easier than ever for parents to get their young children vaccinated in local supermarkets and on the high street by rolling out the vaccine to nearly 4,000 local pharmacies.

In addition, latest figures show less than a third (28.9%) of people with one or more long-term health conditions have had a flu vaccine.

Public health minister Ashley Dalton said: ‘Vaccination is the best form of defence against flu – particularly for the most vulnerable.

‘With flu cases already triple what they were this time last year, I urge everyone eligible to take up one of the 2.4m appointments available next week.'