The Times reported at the weekend it had obtained invoices which appeared to indicate that the contractor was billed ВЈ26,841.20 last year by Ian Kerr, of Droitwich, Worcestershire for information from a "blacklist" of troublesome construction workers.
McAlpine is one of 40 companies accused by the the Information Commissioner of breaching data protection laws by buying information from Kerr.
The commissioner alleges that Kerr charged companies ВЈ3,000 a year to consult his database of 3,213 workers.
Notes about workers on the database included comments against names including “poor timekeeper, will cause trouble” and “Irish ex-army bad egg”.
Sir Robert McAlpine was unavailable for comment.
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