After already booking provisions for the fine in the previous financial year, Erith returned a pre-tax profit of £5.1m in the year to September 2023, compared with a loss of £13.8m in the prior year.

Revenue at Kent-based Erith Holdings grew 9% to a record £227m, with operating margins edging up from 1.7% to 2.1%.

Erith paid out £8.6m during the year to help cover the penalty, and a further £4m instalment after the year-end.

This leaves £5m to be paid in instalments over the next four years under the agreed payment plan.

Chairman Steve Darsey said: “We are pleased to have positively moved forward thanks to the support of both our clients and our long-standing business partners.

“We now have established robust systems within the business rendering it impossible for any further infringements of competition to occur.

“Furthermore, we continue to train all staff involved in marketing, preconstruction, tender submissions and negotiation.

“Refresher training is also underway, under the leadership of our head of compliance.”

The firm also announced a £1.5bn bonus to 436 qualifying staff in the Employee Ownership Trust.

Since becoming at EOT eight years ago the firm has paid out £4.4m to staff.