Hundreds of lives and millions of pounds could be saved if the NHS in England gave care of stroke patients a greater priority, says a report.
Fast diagnostic scans are key
The National Audit Office said stroke care had improved - but too often patients deteriorate unnecessarily.
It said quicker access to scans, drugs and rehabilitation services could boost recovery rates and save a lot of money.
The government promised a new stroke care strategy and action to ensure best practice is spread throughout the NHS.
It is estimated that strokes cost the NHS about £2.8bn a year - more than the cost of treating coronary heart disease.
Annual costs to the wider economy, associated with lost productivity, disability and informal care, are around £4.2bn.
Stroke is one of the top three causes of death in England
Approximately 110,000 strokes and a further 20,000 Transient Ischaemic Attacks ('mini strokes') occur in England every year
There are at least 300,000 people in England living with moderate to severe disabilities as a result of stroke
The average stroke in-patient will spend 28 days in hospital
The NAO report called for efforts to speed up medical care following a suspected stroke, including rapid access to brain scanning.
This, the report said, would help to reduce the risk of death and disability.
But while most hospitals have the capacity to provide scans within 24 hours of admission, most patients last year waited more than two days.
Ambulance and hospital teams rarely provide an effective, integrated response, the report said.
Patients should be seen, if possible, in a specialised stroke unit - but the quality of those available varied greatly, and some were simply not big enough.
The NAO also said that greater use of clot-busting drugs could save many lives.
For instance, if England could match the access afforded by leading Australian hospitals, then more than £16m a year would be saved, and more than 1,500 patients a year would make a full recovery when they otherwise would not have done so.
Better access to rehabilitation services could also improve rates of recovery.
GPs, too, could play a role by referring more people suspected of having had a stroke or a mini-stroke for a scan.
The report also said some scans and interventions are being carried out after the time when they would have been of benefit.
Sir John Bourn, NAO head, said: "Stroke services in England have been improving and there are pockets of excellent practice on which to draw, but many patients are still denied fast and effective treatment and rehabilitation services.
"At £7 billion a year, stroke imposes significant economic costs. By giving stroke the attention and status it deserves, the Department will be able to make financial savings to the NHS and the wider economy."
Care Services Minister Liam Byrne said "We will take action immediately by spreading examples of best practice and will build a future generation of clinical champions through a programme to expand stroke physician training numbers.
"I have asked for work to begin on a new stroke strategy which will deliver the newest treatments and improve the care that stroke patients receive.
"In the meantime, the forthcoming White Paper on out-of-hospital care will put forward proposals to strengthen local care, such as rehabilitation, and ensure services are unified and simple to access."
Jon Barrick, of The Stroke Association, welcomed the report, and said implementing its recommendations would save the NHS money, and reduce "the huge emotional and economic impact upon families and carers".
Dr Gill Morgan, chief executive of the NHS Confederation which represents more than 90% of NHS organisations, said: "The NAO report makes clear that stroke services in England are improving, which is good news for patients.
"The challenge now is to maintain that improvement and ensure that the example set by the best NHS services are followed by the rest."
Shadow Health Secretary and Chairman of the All Party Parliamentary Group on Stroke, Andrew Lansley said: "I strongly welcome the NAO's report.
"We need to improve stroke services, more early intervention, more treatment in specialist stoke units and more intensive rehabilitation - this would reduce death and disability."