MPs on the Commons environment committee yesterday warned that Entrust, the private regulator set up to supervise environmental donations from waste companies to avoid paying the full amount of the landfill tax, could be "unfit" to fulfill the role.

The report follows an evidence session during which the chairman and the chief executive of Entrust were forced to apologise to MPs for interfering with a witness giving evidence to the committee. The witness, Malcolm Aickin, lost his offer of a job with Entrust after telling the committee that the scheme's regulations were "inadequate and inconsistent to the point of incompetence".

Entrust blamed lawyers for not telling them that withdrawing the job offer but them at risk of being in contempt.