A source close to Carillion’s £574m takeover of Alfred McAlpine said there was a “snowball’s chance in hell” of writedowns as a result of the deal.

The claim follows speculation that the £4bn-turnover group would have to write down £400m after a fair-value exercise surrounding the deal.

The process involves deciding how much of the price tag is goodwill and how much assets. Carillion will make an announcement after its half-year results to 30 June 2008.

The source added that there was “no chance” the goodwill element could be subsequently reduced as part of an annual impairment review in December.