Britain's Competition Appeal Tribunal on Wednesday threw out an appeal by Ryanair, which would have blocked regulators investigating the budget carrier's minority shareholding in Irish rival Aer Lingus .
Ireland's Ryanair, Europe's largest budget carrier, had argued that it was not within the UK Competition's Commission's (CC) jurisdiction to investigate its 30% stake in Aer Lingus. This was rejected by the CAT.
The failed appeal runs alongside a fresh takeover bid from Ryanair for Aer Lingus - made in June - as it continues its pursuit of Ireland's 75-year-old former flag carrier.
Britain's Office of Fair Trading (OFT) previously ruled that Ryanair's ownership of a minority stake in Irish rival Aer Lingus threatened competition in the British airline market and asked the CC to consider sanctions.
The CC - unlike the OFT - has the power to force Ryanair to divest its stake.
Ryanair mounted a public takeover for all of Aer Lingus in October 2006, but the European Commission investigated the bid and decided to prohibit it in June 2007.
The commission ruled, however, that Ryanair could not be forced to sell its stake, since Ryanair did not have de facto or de jure control of Aer Lingus.
Ryanair responded to the decision on Wednesday and said it had instructed its lawyers to appeal the ruling of the CAT.
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