Ofcom was at liberty to investigate the issue of "fit and proper" at any time, he added, but would also have to take into account any subsequent undertakings negotiated by the Competition Commission.

BBC: News Corp's BSkyB bid referred to regulator

In a strongly-worded response, the chancellor will say that, under the deal negotiated by his predecessor Alistair Darling with the European Commission over state aid to banks, the government had to sell the majority of its stake by the end of 2013.

BBC: Northern Rock: Osborne to reveal EU deal over 2013 sale

"In view of this considerable opposition, it is clear that the European Commission must step up efforts to find a negotiated solution, " the person said.

BBC: Half of EU members 'oppose China solar tariffs'

The European Commission has put forward new laws to ensure that existing agreements negotiated by individual member states before the Lisbon Treaty are not legally challenged, to maintain the confidence of investors.

BBC: Laws on EU trade agreements

This is clear in Europe, where a directive from the European Commission tells the courts to strike out any unreasonable contractual obligation on a consumer if he has not freely negotiated it.

ECONOMIST: Legal disclaimers