Freelancers who use accountancy firm Christopher Lunn & Company will be updated this week on the ongoing investigation into the firm by HM Revenue & Customs.

The government tax body will write to Christopher Lunn’s clients on 20 August, providing further information on its intentions.The accountancy firm originally informed its clients of the probe last month.

The nature of the investigation is unclear and an HMRC spokesman was unable to comment for legal reasons.

HMRC representatives visited Christopher Lunn’s offices in Crowborough, East Sussex, two months ago, and Broadcast understands that the investigation could be fairly protracted, potentially running into next year. No formal charges have yet been brought against the firm or any of its employees.

Christopher Lunn’s management team has written to customers on two separate occasions to inform them of the issue and make them aware that HMRC may need to check some of their tax returns.

The firm, which is thought to have a significant number of television freelancers on its books, reassured clients that if tax returns were completed appropriately, they will not be charged for any delays in submissions as a result of the investigation.

A Christopher Lunn spokesman said: “Christopher Lunn & Company is co-operating fully with the HMRC investigation and our clients have been supportive during this time. No formal charges have been brought against the company.”