White, who joined Costain in 2021, will become managing director of Mitie’s Technical Services division from 1 December.
He joins the group executive of the engineering maintenance provider, overseeing 16,000 staff delivering services across 350 major contracts – from Heathrow and the MoD to Vodafone and the NHS.
At Costain, White led the Natural Resources division, which grew revenues 7.3% in the first half of 2025 and recently secured major civil nuclear wins with Sellafield and Nuclear Restoration Services.
Costain confirmed that long-serving infrastructure MD Chris Tyerman will take over the Natural Resources division on an interim basis while a permanent successor is appointed.
Mitie chief executive Phil Bentley said: “Sam’s extensive experience and proven leadership in complex engineering environments will be instrumental as we continue to drive engineering excellence and transform the UK’s built environment.”
