Google mistook the NHS's 1.2 million employees for a huge cyberattack and blocked it

The NHS' 1.2 million employees provide some of the best healthcare on Earth - but if you're a big tech provider, that many people can be awfully confusing.

The Register reports that on Wednesday, Google mistook the NHS' network for a cyberattack, and is blocking its access - "intermittently" restricting the million-plus NHS employees' access to the search engine.

In an email, the NHS IT department reportedly wrote: "Google is intermittently blocking access due to the amount of traffic from NHS Trusts Nationally (This is not being blocked by the IT Department). This is causing Google to think it is suffering from a cyber-attack."

In other words, Google is getting hit with so much traffic from the NHS' network, it thinks it is being attacked by hackers, and is blocking it to defend itself.

Hackers often use denial-of-service attacks to try and take down websites and online services. They bombard the target with an overwhelming amount of malicious traffic (often harvested from hijacked computers linked in a "botnet"). If successful, this blocks legitimate traffic from getting through, and crashes the target.

In a statement sent to Business Insider, the NHS confirmed the issue. "We are aware of the current issue concerning NHS IP addresses which occasionally results in users being directed to a simple verification form when accessing Google," it said.

"This would appear to be due to the high number of people using our systems and trying to access Google at peak times. We are currently in discussion with Google as to how we can help them to resolve the issue."

In the email seen by The Register, the NHS advises staff "to use an alternative search engine i.e. Bing to bypass this problem." Alternatively, they can use Google's Chrome web browser and pass a "captcha" test to prove they're not part of a botnet.

Google did not immediately respond to a request for comment.

This isn't the first NHS tech headache recently. In November 2016, its employees were trapped in a "reply-all" email chain - resulting in the sending of hundreds of millions of pointless emails, slowing the network to a standstill.