It also warned that only 42 per cent of patients had brain imaging to confirm their diagnosis within 24 hours of the onset of symptoms.
This procedure is vital as it helps to determine if it is appropriate to prescribe aspirin, which, if given within 48 hours of stroke, can save lives and reduce disability.
Other problems with care include access to therapists and social workers; one-third of patients who have difficulty swallowing are not being assessed by a speech and language therapist within 72 hours of admission or within seven days for those having difficulty communicating.
But the RCP report, which was funded by the Healthcare Commission, found numerous areas of improvement to praise.
There has been a "significant and welcome" increase in the number of patients admitted to a stroke unit at some point during their hospital treatment; 62 per cent in comparison to 46 per cent in 2004.
More hospitals in England now have stroke units, although the RCP claims there is still a lack of capacity.
In Wales however, the number of stroke units has remained the same since 2004 and people are more likely to die from strokes than in England or Northern Ireland.
Commenting on the findings, Dr Jonathan Boyce, head of clinical audit at the Healthcare Commission, said: "This study shows welcome improvements within the last two years in hospital care for people who have suffered a stroke, suggesting that what gets measured does indeed get managed.
"But there is still too much variation, too many places and regions that are not responding as well as they could to minimise the harm done by this serious and common condition. They now need to get their house in order."
And Joe Korner of the Stroke Association said: "While it's great to see a general improvement in stroke care, the latest audit shows that over a third of people who have a stroke never get treated on a stroke unit. Stroke units can halve your chance of dying from a stroke, so it is a scandal that getting treated on one is a matter of luck or your postcode.
"Radical improvements in stroke care are within our reach. The government, with a new stroke strategy in development, has the chance to do for stroke what has been achieved for heart disease in the last ten years. It is vital that stroke gets the priority and investment needed – without investment hundreds will die needlessly."
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