BSkyB faces an inquiry into its purchase of a 17.9 per cent stake in ITV after Alistair Darling, the Trade and Industry Secretary, referred the matter to the Competition Commission.

The satellite company could be forced to surrender some or all of its stake in the broadcaster of Coronation Street or give up voting rights if the commission, under Peter Freeman, the chairman, rules against it. The referral comes after Ofcom, the broadcasting regulator, told Mr Darling that Sky’s investment raised “public interest issues” and gave warning that it could endanger the “plurality of news provision for both cross-media and television news in the UK”.

The Office of Fair Trading argued that the stake effectively merged the two companies and compromised ITV’s independence. The commission will gather evidence from Sky and ITV as well as from Virgin Media, the wider broadcasting industry and consumers. Sky is 39.1 per cent owned by News Corporation, the parent company of The Times.

The case against Sky’s £900 million stake, bought in November last year, was originally flagged by Virgin Media, the rival cable broadcaster. It complained that the action was a deliberate attempt to scupper the £6 billion takeover of ITV that Virgin was pursuing at the time.

Mr Darling took the unprecedented step of requesting the Ofcom inquiry in February this year, invoking the “public interest test” for media mergers in the Communications Act 2003.

The commission said that it was expecting a “higher than usual” response from consumers to its invitation for submissions because of the continuing high-profile dispute between BSkyB and Virgin Media that has left three million Virgin customers without basic Sky channels.

Mr Darling said: “My decision reflects consideration of the reports I have received from both the Office of Fair Trading and Ofcom and of other representations I have received about this matter. On the basis of the evidence before me, a fuller investigation by the Competition Commission is justified.”

A verdict is due in December. Mr Freeman will report preliminary findings in about four months, but he has 24 weeks in which to submit a full report to the DTI. The Trade Secretary must then make a decision based on the findings within 30 days.

Mr Freeman has chaired four merger-and-acquisition cases in the past, all of which were cleared. In 2005 he cleared the purchase by Archant of local weekly newspapers in the London region that had been owned by Independent News and Media.

If the commission rules in favour of Sky, it could be told to do nothing or it might face a further restriction on the maximum stake that it can keep. Sky cannot own more than 20 per cent of the broadcaster.

Under inquiry rules, Sky must now seek permission from the DTI if it wants to sell some or all of its ITV share-holding before the investigation concludes.

A Competition Commission official said: “If Sky doesn’t think it has done anything wrong and that it took the stake for a good reason, then it would want to see the inquiry through to the end.”

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