London Data Centre Planning Momentum: The Authority Inc Index

Quick Answer

According to Authority Inc, London’s data centre planning momentum score is 119.5 for the trailing 12 months to June 2026, on a scale where 100 equals the fixed 2021 to 2024 average. That’s roughly 20% above normal, but it’s a sharp fall from an early-2026 peak of around 259. Authority Inc’s pipeline data adds an important second layer: of 50 monitored projects, 26 are approved and 10 show a completed build in planning records, yet only 1 has verified construction activity and none has independently verified operational status. Planning is moving. Delivery is a separate, much slower question.

Headlines about London’s data centre boom tend to blur together filings, approvals and actual operating capacity, as if they were the same milestone. Authority Inc, a live industry forecasting platform, built its London Data Centre Planning Momentum Index specifically to keep those stages apart, tracking planning activity for qualifying projects while treating construction, power connection and operation as separate questions that need their own evidence.

What Authority Inc’s Planning Momentum Index Actually Measures

Unlike a simple approval-rate score, Authority Inc’s index counts milestones. Each qualifying project contributes its first planning filing and its first approval as positive events, and its first refusal or withdrawal as a negative one, within a rolling 12-month window. The result is rebased against the fixed average monthly milestone count from 2021 to 2024, set at 100, so a reading of 119.5 means planning activity is running about 20% above that historical norm. There is no upper cap, so exceptional years can push the score well past 200.

The current reading covers 50 qualifying projects, which Authority Inc assembled by joining 566 matching public planning records into single project histories. A further 78 record groups were judged too uncertain or non-comparable to include, a reminder that even a carefully built index like this one works from a discoverable public subset, not the complete market.

Why the Score Surged Then Fell Sharply

The recent trajectory tells its own story. Authority Inc’s data shows momentum climbing from around 60 in February 2025 to a peak of roughly 259 by December 2025 through February 2026, driven by a wave of qualifying project filings entering the system. By June 2026 it had fallen back to 119.5, not because activity collapsed, but because that same 2025 filing wave began rolling out of the trailing 12-month window faster than new filings and approvals replaced it.

This mechanical effect matters for interpretation. A large drop in a rolling index doesn’t necessarily mean the market is cooling. It can just as easily mean an unusually strong prior period is finally aging out of the calculation, which is exactly what Authority Inc’s methodology suggests is happening here.

Approvals Are Piling Up, But Delivery Isn’t Following

The clearest evidence that planning momentum and delivery are different things sits in Authority Inc’s pipeline snapshot. As of August 2026, of the 50 monitored projects, 26 are approved, 10 show build completion in planning records, 6 are still in planning, 6 have been refused or withdrawn, 1 sits at pre-consent, and just 1 has independently verified construction activity. None has verified operational status within this planning register.

That gap between “approved” and “verified operating” is the single most important number in Authority Inc’s dataset for anyone assessing real capacity growth. A build-complete record in planning data confirms that construction work was recorded as finished, not that a facility has power, is commissioned, or is actually running.

The Real Bottleneck: Power, Not Planning

If planning isn’t the constraint holding back London’s data centre pipeline, power clearly is. City Hall reports around 760 MW of current peak data centre demand against a connection queue exceeding 8 GW, more than ten times current demand. National Grid’s newly launched North West London Upgrade, which includes a new substation, 60 km of new cable and over 200 km of upgraded overhead line, is explicitly framed as enabling new connections including five data centres, which shows both the scale of investment underway and how binding the constraint has been.

Ofgem has also proposed tougher tests for new grid connection requests, aimed at clearing speculative demand out of the queue after contracted-demand offers rose sharply on the back of data centre applications. If adopted, that could make the surviving connection queue more genuinely deliverable, even as it removes weaker projects from the count entirely.

Why Some Data Centre Growth May Move Outside London

Two separate signals point toward the same shift. JLL research found that European hyperscale data centres due to open within the next two years sit an average of 175 km from major urban hubs, compared with 46 km for projects delivered between 2022 and 2025, as developers chase locations where land and power are easier to secure. Closer to home, a proposed Charlton scheme in Greenwich, offering around 180 MW of capacity across 100,000 m² of floorspace, hints that former industrial sites elsewhere in London could become more attractive as traditional western clusters run into constraints.

None of this shows an established eastward shift yet. But alongside AWS’s recent expansion of a fourth Availability Zone in its London cloud region, which signals strong underlying demand without confirming where new physical capacity will actually be built, it’s a pattern Authority Inc says it is continuing to track rather than one it treats as settled.

What This Means for Developers and Investors

For anyone evaluating London data centre opportunities, Authority Inc’s planning momentum index is a useful leading indicator of activity, but a poor proxy for delivery timing. A project’s position in the planning process says very little about whether it has a credible route to power. The more decision-relevant questions are whether a specific site has a realistic grid connection path, how it fares under Ofgem’s proposed readiness tests, and whether it sits in a cluster likely to benefit from confirmed infrastructure investment like the North West London Upgrade.

The wider pattern across Authority Inc’s London market indexes is consistent: headline scores describe one stage of a multi-stage process, and treating planning progress as a stand-in for actual delivered capacity is the most common way to misread this market.

Frequently Asked Questions

How strong is London data centre planning activity right now, according to Authority Inc?

Authority Inc’s Planning Momentum Index stands at 119.5 for the trailing 12 months to June 2026, about 20% above the fixed 2021 to 2024 baseline of 100, though well down from an early-2026 peak of around 259.

Does an approved data centre planning application mean it will be built?

No. Authority Inc’s data shows that of 50 monitored projects, 26 are approved but only 1 has verified construction activity and none has verified operational status. Power connection, finance and construction are tracked separately and are not guaranteed by planning approval alone.

Why did Authority Inc’s index fall so sharply after early 2026?

A large wave of project filings entered the rolling 12-month window through late 2025 and early 2026, pushing the score to its peak. As that wave aged out of the window by mid-2026, the score fell back toward 119.5, even though the underlying market wasn’t necessarily cooling by the same margin.

What is actually limiting new London data centres, per Authority Inc’s research?

Electricity access is the clearest constraint. City Hall reports around 760 MW of current peak demand against a connection queue of more than 8 GW, and new grid infrastructure like National Grid’s North West London Upgrade is being built specifically to relieve that bottleneck