But major firms are predicting a stronger year ahead as data centre work, commercial retrofits, life sciences and lab work starts to fire-up the sector.

The industry’s biggest players are also taking on major contract roles on data centre work as £100m-plus M&E packages hit the market.

During last year, Dalkia leap-frogged NG Bailey to become the industry’s biggest player after a rebrand that consolidated the Imtech, Inviron and SPIE UK brands.

Wates-owned SES, Skanska’s SRW and Gratte Brothers enjoyed strong sales growth lifting the firms up the rankings to now sit just below the big three.

Last year’s challenging business environment of inflation, shortage of workers, project delays and supply chain disruptions saw Michael J Lonsdale become the sector’s highest-profile casualty.

Other firms going under included London’s Haydon ME, York’s JDL Electrical, Plumbing & Heating and Bradford-based H Mitton and Newcastle’s
Norstead.

The top 30 firms saw a record six newcomers last year with four operating in London and south east.

The Top 30 is compiled for trade body BESA by Gokhan Hassan, Managing Director at Chartered QS practice, GHCS