The Gerrards Cross headquartered group lifted revenue 27% to £1.19bn in 2025 while pre-tax profit climbed 15% to £48m, driven by rapid expansion of its international data centre business.

Jackie Wild, Group CEO said: “2025 was a year of strong growth across the Group, driven by our valued client and supply chain partnerships and sustained focus on consistent delivery.

“We also continued to invest capital in the business to enable our sustained growth as we deliver complex projects across a wide international footprint.

“With a strong pipeline confirmed for 2026 and beyond, including major capital projects spanning several years, we remain focused on delivering technical construction and engineering excellence for our clients.”

The main UK contracting business, TSL Ltd, increased turnover 12% to £592m, and is forecasting revenue to top £600m this year on the back of a strong secured pipeline.

Pre-tax profit at TSL Ltd slipped to £25m last year from £27m as the mix of projects weighed on operating margin which eased from 5.0% to 3.9%.

Despite this, the UK division strengthened its balance sheet, growing cash reserves to nearly £70m while increasing its workforce by almost 48% to 372 employees.

During the year TSL delivered two major facilities for Greggs, completed a robotic fulfilment centre in the North East, handed over a major South East data centre and finished an aircraft engineering hangar for Jet2.

Elsewhere, work began on a fourth manufacturing facility at SmartParc SEGRO Derby for a major international food producer, while the business continued to expand in automated logistics, cold storage, advanced manufacturing and pharmaceuticals.

After the year end, TSL sold its Rockland Concrete division in a trade and asset deal, disposing of a business that generated around £20m of revenue in 2025 as it sharpened its focus on specialist technical construction.

Across the wider Tonroe Group, growth was driven by the international data centre division, which secured work on one of Europe’s largest hyperscale campuses in Portugal alongside major projects in Germany, the Netherlands, Belgium and Spain.

Overseas work now accounts for just over half of group revenue at £608m.