Britain's doctors are about to announce a breakthrough. They have agreed on what information should go into our online medical records.

The decision could change the face of healthcare. The basic idea, set out by the prime minister nearly five years ago, is that if you live in Manchester but happen to get run over by a bus in Torquay, emergency crews should have access to your medical records. Such information could be a life-saver, especially if you are on medication or are allergic to antibiotics.

Nearly everyone thinks this is a good idea. But designing a useful, universal electronic health record is not a trivial problem. There's no point in merely networking existing NHS systems, even if it were technically possible. In any case, there is no way to guarantee that a record applies to a particular individual, especially if they have a common name.

Further, records contain information - about mental health and sexually transmitted diseases, for example - that patients gave in confidence and don't want shared.

For these reasons and more, doctors the world over have been wrestling for years with the terminology, content and scope of electronic records.

Last week, Peter Hutton, chair of the Academy of Medical Colleges, which represents some 90,000 doctors, announced a breakthrough. A working group has reached agreement on what will go into a system called the integrated health information spine. The spine is one of the new NHS IT services being set up by the £2.3bn national programme for IT.

Professor Hutton told the Healthcare Computing 2003 conference that the spine will contain four elements making up a womb-to-tomb health record. They are:

· Basic personal details, tagged with the 10-digit NHS number. (Issued at 28 weeks' gestation, rather than at birth as at present.)

· Crucial health information, such as blood group and allergies.

· Summaries of medical treatments: a note, for example, that a particular operation had taken place. Detailed records, such as test results, would continue to be held locally.

· A list of GPs and other NHS organisations with which the patient is registered.

The data will be extracted from current systems and made available across the NHS's intranet to anyone with the right level of clearance. It will also be available to the patient whenever they want.

One issue remains to be solved: that of control. Today, the NHS operates on a muddy assumption that patients give "implied consent" for their information to be shared. This is legally questionable. New rules, due to be published this summer, will give patients control over what goes onto the spine and who is able to see which pieces of information. In some cases, this may be a named individual rather than a category such as "A&E doctors".

With the specifications and rules of access for the spine agreed, all we have to do is build it. It would be nice if that turned out to be the easy bit.