Almost 40% of people attending A&E and minor injury units leave without needing any treatment, according to a new report.

Data from the NHS Information Centre for England shows many people leave these departments having only received advice.

Of the 10.3 million visits in 2009-10 where details were recorded, around 3.9 million ended with the patient receiving guidance.

Another one in eight - 1.2 million - were recorded as requiring neither advice nor treatment.

The report covers 15.6 million records from A&E departments, minor injury clinics and walk-in centres.

It represents about three-quarters of emergency and unplanned activity in the NHS and covers 172 of 263 providers of emergency services in England.

The study also showed around half a million patients leave A&E or injury units before being treated.

The busiest time in A&E is 10am on a Monday morning, with patients typically spending around nine minutes in the department before being assessed.

They stayed there for 55 minutes before being treated and just over two hours before they get to go home.

NHS Information Centre chief executive Tim Straughan said: “This is the third year we have been able to publish detailed A&E information - offering an illuminating insight into the scale and type of activity taking place after a person comes through a department’s doors.

“This report highlights the scale to which A&E staff offer advice and reassurance to patients, rather than give any medical treatment.

“It also shows a significant number of patients were recorded as leaving the department without having had any advice or treatment.”

A spokeswoman for the Department of Health said: “We welcome the availability of this additional data on accident and emergency services.

“It will add to the intelligence that helps the NHS drive improvements in the quality and delivery of its services to patients.

“In future, the NHS will focus on measuring its performance on what matters most: patient outcomes.

“With the help of clinicians, we have developed a set of clinical quality indicators for measuring A&E performance so that the right balance can be struck between the focus on outcomes, clinical quality, safety, patient experience and timeliness of care.”