Café chain Patisserie Valerie has announced it has discovered “significant, and potentially fraudulent, accounting irregularities” and the existence of a winding-up petition issued against one of its subsidiaries by HMRC.

The tax authority is seeking £1.14m in taxes, the company said, while it confirmed it had suspended its finance director Chris Marsh. The winding-up petition is against Stonebeach, its principal trading subsidiary, and had been filed at the High Court of Justice on 14 September. It was listed in the London Gazette, the official government bulletin, on 5 October. Shares in the company have been suspended.

Company chairman Luke Johnson said: “We are all deeply concerned about this news and the potential impact on the business. We are determined to understand the full details of what has happened and will communicate these to investors and stakeholders as soon as possible.”

Patisserie said it and its advisers are in communication with HMRC with the “objective of addressing the petition”.

The company warned that the accounting irregularities could have led to “potential material mis-statements” of its accounts.

“The company continues to engage with its professional advisers to understand better the financial position of the group and will make further announcements in due course,” it said.

It also warned the irregularities could lead to a “material change in its overall financial position”.