The board said Bingham, who took up the CEO role just four months ago, had been suspended while a full investigation, supported by professional advisers, is carried out. No further details of the allegations were disclosed.

Non executive chair Vijay Thakrar has taken over as interim executive chair with immediate effect, supported by the group’s divisional managing directors and chief financial officer to ensure business continuity.

The leadership shake-up came as Alumasc said trading for the year to 30 June remained broadly in line with downgraded market expectations despite tough construction markets.

Revenue is expected to fall to around £107m from £113m last year, while underlying pre tax profit is forecast at about £10m, down from £14m.

The group blamed weaker demand on affordability pressures, planning delays and continued geopolitical uncertainty, saying customers had postponed project decisions and delayed call offs during the final quarter.

Water Management was the weakest performing division, with revenue down around 16%, although the decline narrowed to about 3% after stripping out the prior year’s major CLK Airport project in Hong Kong. Alumasc said commercial and operational improvement measures were already beginning to have a positive impact.

Building Envelope held revenue broadly flat, while Housebuilding Products grew sales by around 16%, helped by market share gains, customer service improvements and new product launches.

Despite lower earnings, Alumasc ended the year with a 49% larger order book than a year earlier and net debt of about £7m.

The company said the stronger pipeline and ongoing performance improvement initiatives left it well placed for the new financial year, although it remains cautious over market conditions. A further update on both trading and the investigation into Bingham will be provided in due course.