none of these are enough to guarantee that the wrong people won't look at your medical history. Smartcard systems tend to be undermined by users who stay logged in to save time. And while there are rules about whose records staff can look at, there can't be any actual blocks, or the system would be useless in an emergency.

As a result, argues Douwe Korff, professor of international law at London Metropolitan University, the database could fall foul of the European court. "It's not good enough to say it shouldn't happen," he says. "They need to take reasonable measures to ensure patient confidentiality."

Campaigners have called on the government to scrap plans for a single database. They say that linking up existing GP records could provide many of the same benefits, but reduce the odds of frightening headlines in the Daily Mail.

So far, though, the government has shown little appetite for the change, and if it is concerned about the legal situation it isn't showing it. It says the ruling will have no

impact on policy. It has even dropped hints about making the database even bigger, by opening it up to social workers. The Department of Health has consistently refused to publish legal advice which it says shows the system is lawful. As a result, a test case could be needed to clarify the situation.

That would take time. But if a British court did find against the database, the government could be forced to junk the whole thing. That £6bn investment might be no more secure than your medical records.