The British government today ordered Bskyb to reduce its 17.9 per cent stake in ITV to below 7.5 per cent because it hampered competition in the UK television market.
The ruling could cost Bskyb around £250 million if it sold at yesterday's closing share price, since the value of the shares has dropped since it bought them.
ITV welcomed the ruling and said it was in the best interests of the overwhelming majority of its shareholders.
Secretary of State for Business and Enterprise John Hutton said he had decided to impose the remedies recommended by the Competition Commission to address the "substantial lessening of competition" identified in their report.
He also required behavioural undertakings from Bskyb, ordering the company not to dispose of the shares to an associated person, nor to seek or accept representation on the board of ITV and not to re-acquire shares in the broadcaster.
Bskyb has up to four weeks to contact the Competition Appeal Tribunal if it decides to appeal.
Bskyb, Britain's dominant pay-TV firm, paid 135 pence per share, or £940 million, for its stake in ITV in November 2006. The move effectively blocked cable group NTL - since relaunched as part of Virgin Media - from buying ITV.