Hospitals are "full to bursting" in England, creating a potentially dangerous environment for patients, an analysis by experts suggests.

Hospitals should run at about 85% capacity to give them room to cope with surges in demand, and figures show the NHS average hovering around that mark.

But analysts Dr Foster said the figure was skewed by quiet periods and rose higher if they were stripped out.

Ministers denied the NHS is overcrowded and said it could manage demand peaks.

According to the analysis, if only midweek figures are taken into account, the average capacity figure for 2011-12 was 88%.

It rose to 90% if holiday periods, such as the royal wedding and Christmas, were stripped out, Dr Foster said.

The private research group said this was important as the quiet periods were helping to mask the fact that many trusts were now too full for long periods of the year.

Its report, which excluded specialist centres but included 145 hospital trusts, said when hospitals were too busy patient care suffered because systems started breaking down.

Dr Foster co-founder Richard Taylor said: "When that happens, patients are put in whatever bed can be found, orderly management of admission and discharge can become strained, infections are harder to control and mistakes are more likely to happen."

Gotta love the rationale that says, 'if we throw away all the periods when the hospitals aren't full and only look at the times when they are full, we can clearly demonstrate that the hospitals are full'

Gotta love the rationale that says, 'if we throw away all the periods when the hospitals aren't full and only look at the times when they are full, we can clearly demonstrate that the hospitals are full'