Fields next to Junction 24 as well as Junction 23 alongside M25 motorway are being proposed as sites for new data centres  

Plans are being prepared for a second multi-million-pound data centre to be built north of High Barnet on green belt farmland beside the M25 motorway.

Orbital Data Centres is proposing to spend £1.5 billion constructing and fitting out a 50,000 square foot data centre just south of Junction 24 on a 29-acre site between the motorway and The Ridgeway – see illustration above.

An application by US tech firm Equinix to build a much larger data centre on an 85-acre site to the north of Junction 23 is already in the early stages of consideration by Hertsmere Borough Council.

The Junction 23 centre, which would cost £3.9 billion, would almost fill the fields between South Mimms service station and Dame Alice Owen’s School at Potters Bar.

The proposed Junction 24 centre, to the south of Potters Bar, would be the first to be built by Orbital Data Centres.

Approval would be needed from both Hertsmere and Enfield Borough Council as the site straddles the boundary between the two authorities.

Orbital purchased the site, described as dis-used farmland, from Enfield Council earlier this year.

After public consultation on the plan during November, the company hopes to submit its planning application before the end of the year with construction due to be completed by 2030 when the centre is scheduled to be supplied with its own electricity grid connection and substation.

At a public presentation of the plan, Orbital said the new centre would not draw from the local electricity network, and it would be cooled with a closed-loop system which would circulate the same water and not draw on the local mains supply.

Over half the 29-acre site would remain as open space with wooded, wetland and grassland around the data centre with the addition of 640 new trees. Five acres would be open to the public with footpaths through the site.

Preparation of the site and construction of the two data centre buildings would provide 1,400 to 1,700 jobs during the three years of construction.

Once in operation, the centre would provide 170 jobs with around 85 more in the wider area.

Orbital calculate the new centre would provide a £30 million a year boost to the local economy. This would include £6.8 million in business rates of which £2.7 million a year could be kept for local services.

Orbital’s planning consultants acknowledged that having to seek planning permission from two separate authorities was a complication.

The western half of the site is within Hertsmere. Although previously green belt, the site is now regarded as grey belt and has been designated for employment use, which includes data centres.

However, there is a dispute about the status of the eastern half of the site within Enfield.

Under the Enfield local plan, it was originally designated for employment use, but a planning inspector subsequently proposed that designation should be removed as it would result “in a very high degree of harm” to green belt land around Junction 24.

In the view of Orbital’s consultants, the subsequent declaration by the government that data centres should be considered critical national infrastructure would now have to be taken into consideration, along with the new procedure for redesignating green belt as grey belt.

Outline planning permission for the much larger data centre near Junction 23 – to be known as the Hertfordshire Campus – was granted in 2025 and Equinix is now involved in detailed discussions with Hertsmere over the infrastructure which be required.

Public consultation on the Junction 24 centre closes on 22 November.

 For more details of the two proposed schemes:

www.junction24datacentre.co.uk

www.equinixtogether.com/hertfordshire/