One in every 10 trips to A&E last 12 hours or more, previously hidden figures have shown.
For the first time, the NHS has published data showing the precise lengths of visits to emergency departments - from the moment a patient arrives to the point they either leave or are admitted onto a ward.
Previously, official figures have only shown the period of time from when a person is first assessed by A&E staff to when a decision is made about their care.
Also known as 'trolley waits', this meant statistics previously did not include any time spent waiting for an assessment - be that in waiting areas or the back of an ambulance.
In Norfolk, the statistics have shown that on average one in every 10 patients will spend at least 12 hours in the entrenched departments - with a slightly higher rate at the region's biggest hospital - the Norfolk and Norwich.
In February, which the latest figures relate to, 1,165 out of 9,370 A&E trips lasted more than 12 hours - a rate of 12pc.
At the Queen Elizabeth in King's Lynn this figure was 11.2pc (635 out of 5,670) and at Gorleston's James Paget it was 10.3pc (585 out of 5,660).
However, while the region's hospitals are seeing some of the slowest ambulance handover times in the country, this new metric shows a similar picture to the rest of the nation.
A spokeswoman for NHS Norfolk and Waveney said: "The data reflects the significant demand we are seeing in emergency departments, with the most recent winter being one of our busiest on record.
"Key to reducing the amount of time people wait for admission to a hospital bed is improving how patients flow through our hospitals and are discharged.
"We have therefore focussed on increasing community bed capacity and providing extra support at home to help with this."
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