Mace’s group deputy chief executive Jason Millett is taking temporary charge of the firm’s construction business after previous boss Andrew Jackson left yesterday.

His shock departure comes just over three months after he was promoted to the top job at the construction division in July.

Millett will carry out the role until a successor is appointed. Construction is Mace’s biggest business with a turnover of £1.7bn last year out of an overall income of £2.4bn.

Andrew Jackson joined Mace in 2015 and was made chief executive of its construction business in July

Previously the division’s chief operating officer, Jackson arrived at Mace in 2015 from Laing O’Rourke after originally joining John Laing as a trainee in the late 1990s.

Jackson replaced Gareth Lewis who had been at Mace 27 years at the start of July.

His appointment came as part of a wider rejig at the business over the summer with Millett, who had led the consult division for the past five years, becoming chief executive-designate. He is due to take over from Mark Reynolds next January who will become executive chair.

In a statement, Mace said: “Mace Group has announced that Andrew Jackson, CEO for Construction, is stepping down from his role for personal reasons.

“Jason Millett will take up a temporary role as interim CEO for Construct, supported closely by Construct’s chief operating officer Stephen Jeffery, and the business unit managing directors from Construct.

“Jason will combine the role with his current position as deputy chief executive, and his transition to group chief executive will continue as planned in January.”

Mark Reynolds, Mace’s chairman and chief executive, added: “I would like to thank Andrew for his hard work and commitment over the last nine years, supporting and leading Mace Construct through a period of major growth. He has made a positive impact on our teams and to our construction business. We wish him well in the future.”

Millett’s job at consult was taken by Davendra Dabasia who had been COO since the start of last year, having joined the firm from Lendlease in 2007.

Mace said it wants revenue from its consult business, expected to be around £700m this year, to be over the £1bn mark by 2030 with the division eyeing income of £1.2bn at that point.

Consult currently employs around 5,500 people across the globe on top of the 1,850 employed by construct with Millett saying the group’s overall employee number could reach 10,000 by 2030.

Construction will still be the firm’s biggest business by revenue at the start of the next decade with income of around £2.4bn.