NTT has decommissioned a legacy data center outside London.

According to a filing this month with the UK Environment Agency, NTT Global Data Centers EMEA UK Limited is partially surrendering the environmental permit associated with its four data centers in Hemel Hempstead in Hertfordshire.

The company is removing its HH1 (Centro) data center, located at 3 Boundary Way, from the permit.

According to the filing, the data center was decommissioned during 2024 and completed in November 2024. The closure included the removal of four diesel generators totaling 3.5MW, fuel and fuel storage, and the removal of refrigerants (F-gases) from refrigerant systems.

HH1 is no longer listed on NTT’s website. The company hasn’t publicly announced HH1’s closure, but Colo-X noted the facility was no longer open as part of its visit to NTT’s other facilities in the London area last year.

DCD has reached out to NTT for comment.

NTT took over the HH1 site when it acquired Gyron Internet in 2012 – the Gyron name was retired in 2019.

The single-story facility – a retrofit of an existing industrial building – was Gyron’s first self-built data center and launched around 2009. The air-cooled site offered 2.1MW of IT capacity across 700 sqm (7,535 sq ft) of IT space, according to an NTT sales brochure.

NTT still operates the HH2, HH3, and HH4 facilities in Hemel Hempstead, and also operates data centers around the wider London area in Slough and Dagenham.