The UK government’s internet surveillance centre, GCHQ, may be aware of many things, but the need for an environmental permit for its backup power generators is not among them. The site’s generators do not have the necessary paperwork and so are being run unlawfully, it has been revealed.

GCHQ – Government Communications Headquarters – in Cheltenham is the secret services’ listening station and in 2013 Edward Snowden revealed to the Guardian the vast amount of data it harvests from fibre-optic internet cables. As a result, GCHQ’s data centre is one of the largest in the UK.

Big data centres require a robust back-up electricity system in case of power cuts. These are provided by an array of diesel generators that emit exhaust fumes when in use. For some years, those above a certain small size require permits from the Environment Agency, under the Industrial Emissions Directive (IED), which regulates air pollution.

However, trade publication The Ends Report discovered that GCHQ has failed to obtain such a permit. The Environment Agency (EA) confirmed this to the Guardian and said it was investigating the matter.

The EA said it was the responsibility of generator operators to apply for such permits. GCHQ had not responded to a request for comment at the time of publication.

The data centre sector appears to have only recently realised the need for permits. But a number of centres have obtained permits in the past couple of years, including Digital Realty’s in Woking and, in London, Telehouse’s facility and Thomson Reuters’ Docklands Technical Centre.

“While one might expect government data centres to set an example in compliance it appears that they are lagging behind commercial operators,” said Emma Fryer at technology industry association techUK. “I doubt that this is a case of ‘do what I say, not what I do’. I suspect it may be down to lack of awareness,” she told The Ends Report.

Diesel farms are highly polluting ways to generate power but at data centres they are rarely used, except for testing. The IED regulations were developed primarily to cover emissions from always-on power stations, not units used only occasionally.

“While it is absolutely essential to address local air quality issues, applying the IED in its full glory to emergency standby plant that is barely used is disproportionate,” said Fryer. She said it can cost over £100,000 to gather the data needed to obtain the permit.