Airport operator BAA has lost its latest challenge against a ruling that it must sell Stansted and either Glasgow or Edinburgh airports.
BAA has mounted a string of legal challenges in an attempt to keep them ever since the Competition Commission ruled in 2009 that BAA must sell three of its seven UK airports.
The ruling has already led to BAA selling Gatwick Airport.
The Supreme Court ruled against its latest bid to stop further sell-offs.
BAA was asking the court - the highest in the UK - to give it leave to appeal against a previous Court of Appeal decision that it should be forced to sell two more of its key hubs.
A BAA spokesman said: "We are disappointed by the Supreme Court's decision not to hear our appeal.
"We continue to make the case to the Competition Commission that the circumstances in which they found reason to force the sale of airports have changed significantly since early 2009 and should certainly be reviewed in the light of the Government's policy to rule out new runway capacity in the south east of England."
The Competition Commission said in a statement that it was examining whether there had been any significant developments since the original decision back in March 2009 that could cause it to reconsider.
It said BAA and other interested parties had submitted their views and that it should report back towards the end of next month.
Spanish-owned BAA operates Heathrow, Southampton and Aberdeen, as well as Stansted, Glasgow and Edinburgh.