The dispute was raised in Parliament this week when Transport Secretary Heidi Alexander said an HMRC investigation was underway following an internal HS2 probe into labour supplied to Balfour Beatty Vinci (BBV) in the West Midlands.

But Danny Sullivan Group said it has received “no communications” from HMRC and an external-led review commissioned by the firm has found it is fully tax compliant.

A company statement said: “As a business with a long and reputable history, we have treated these allegations extremely seriously and have investigated the contractual compliance issues raised. These specifically relate to the erroneous engagement of Construction Industry Scheme (CIS) workforce operatives on HS2 where we provide skilled trades and labour.

“As part of this work, we commissioned an externally-led review by a leading professional services firm, assessing matters of contractual compliance as well as undertaking an independent review of internal governance and controls.

“The findings and recommendations of this report have been shared with our trusted clients, and where mistakes have been made, we have and continue to put these right. This includes having taken all the necessary steps to ensure full contractual compliance.

“Throughout this process, no evidence of bribery or deliberate wrongdoing involving any employees of our business has been identified.

“Danny Sullivan Group also wishes to address recent speculation and confirm that we are fully compliant with all tax obligations, and are confident that all relevant taxes have been – and continue to be – paid.

“The issue under discussion has been focused on the application of worker type classifications under our contractual agreements. As a large employer and trusted partner of some of the UK’s biggest infrastructure companies, we take our responsibility to uphold the highest standards of governance to all our stakeholders extremely seriously.

“We are confident that our robust response and substantial investment in resolving these issues will ensure that we emerge from this situation a stronger and better company with best-in-class compliance and governance processes.

“Our work continues on the landmark HS2 projects and many other critical infrastructure projects with our long-standing clients and partners across the UK.”