The proportion of patients admitted from accident and emergency units without first being assessed or treated has more than halved since the four hour target was introduced.

This is according to an analysis, shared exclusively with HSJ, that suggests the target is not being “gamed” to the extent many believe.

Most A&E departments have now changed the way they work so they expect to have patients fully investigated by two hours

The analysis of reference costs data shows that between 2004-05 and 2008-09, A&E admissions rose from 22 per cent to 26 per cent of patients.

The earlier figures are likely to be lower as they include patients who died as well as those who were admitted.

But the proportion of those who were not investigated or treated before admission dropped from 37 per cent to 15 per cent.

The figures appear to counter fears that large numbers of patients are being admitted unnecessarily to avoid a breach of the target.

Homerton University Hospital Foundation Trust A&E consultant Simon Eccles said: “When the four hour target first came in there were still large numbers of people who were admitted without being investigated.

“Most A&E departments have now changed the way they work so they expect to have patients fully investigated by two hours, leaving time for specialist opinion and the process of admission to occur smoothly.”

He said it was difficult to “game” investigations data. “It doesn’t matter how you look at it, these look like good figures”, he said.

Some patients, such as those with cancer, often needed to be admitted immediately, meaning it would never be possible to investigate everyone.

The Conservative Party has recently led attacks on the target to transfer, admit or discharge 98 per cent of A&E patients within four hours.

Party leader David Cameron said at a King’s Fund event last December that he had personal experience of his son being admitted from A&E inappropriately.

Dr Eccles said the target had reduced waiting times and should not be scrapped, but also said that it would benefit from greater flexibility, for example excluding patients with certain conditions.

Getting from 95 to 98 per cent compliance took up around half of the workload associated with the target, he said.

RSR Consultants director Richard Russell, who carried out the analysis, said: “A lot of people are banging on about the target but we’re doing more in A&E than ever before.”

But the target was not right for everyone, he said.

He suggested that an A&E referral to treatment target would keep waiting times down without encouraging inappropriate admissions.