Construction firm Kier has found a huge hole in its finances — revealing a further £40.2m of debt than previously thought.

Kier has been forced to restate its debt position which was reported at the end of 2018 at £130m but has now been revised to £180.5m.

The firm has two hubs in Norfolk, one in Norwich at Mile Cross Lane and one in Aylsham.

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The Kier Group said that the debt had been unearthed following an 'accounting error related to property assets'.

The average month-end debt position for the six months ended December 31 was also increased to about £430 million from £370 million.

Following the announcement, shares crashed by more than 13% in morning trade to 431p.

Kier said it remains focused on reducing its debt and expects that it will be in a cash position by June 30.

Meanwhile, the company said it expects to book a £25 million charge in its interim results linked to the Broadmoor Hospital redevelopment after reaching an agreement with the client over additional costs linked to the project's delay.

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Kier also said it is on track to meet expectations for the full year, with results weighted towards the second half, despite 'current political and economic uncertainty in the UK, and the implications for third-party investment'.

Interim results are expected to be published on March 20.