Part-way through a review that is taking longer than Terminal 5 check-in, the Competition Commission has said that there is a “very real prospect” that it may force BAA to sell off some of its seven UK airports. This should come as welcome news to passengers whose experience of these airports is increasingly one of queueing, queueing and queueing again at understaffed departure desks, cramped security channels and empty baggage carousels, in between brightly lit, well-staffed shopping arcades. This monopoly has not put passengers first.

The case for breaking up BAA is compelling. There is no economic reason why one company should control about 63 per cent of all flights to and from Britain. Nor will any national security arguments fly, now that BAA is owned by the Spanish company Ferrovial. Increased competition could bring immense benefits, just as it did to the telecoms and airline industries.

BAA argues that its monopoly position has enabled it to provide strong investment. But it also admits that the industry is short of capacity, which in itself is a drag on competition. It is perfectly possible that BAA's dominance of southeast England, where it handles almost 90 per cent of passenger flights, has blunted its readiness to push for expansion. Investment would be more likely to flow to where it is most needed if airports were competing with each other. Moreover where airlines are concerned, the grandfathering of certain slots means that there is almost no competition in long-haul flights. BAA's “use it or lose it” approach has led to the disgraceful practice of airlines flying virtually empty planes to retain coveted slots at Heathrow and Gatwick, at a time when the industry professes to be concerned about climate change.

Break-up is overdue, but break-up alone will not guarantee an improved passenger experience. Each airport will need to be tightly regulated if it is not simply to become a monopoly in its own right. Even if Gatwick were sold, (which must now be an odds-on possibility), the new owner would still enjoy a monopoly at Gatwick unless there are dramatic changes in the way airports are regulated.

At the moment, BAA clearly sees the airlines, not the passengers, as its customers. Shops crowd out passenger seating and toilet facilities. The latest tales of woe from Terminal 5, about everything from lost baggage to vast queues for lacklustre lavatories, only emphasise the need to reshape the airport's priorities.

The Civil Aviation Authority is responsible for airspace policy and safety regulation as well as consumer protection, and its fines have rarely made the authorities feel passengers' pain. It would be better to create a new regulator - an OfJet or OfAir or even Sound-Of - to focus solely on enforcing passenger standards. Its remit should also include the airlines, to prevent a recurrence of the recent buck-passing between BAA and BA over T5. Airlines still dominate, and monopolise service, on many routes and the tendency to treat customers like cargo is the result.

Previous efforts to break up BAA's monopoly have foundered on doubts about whether that was in the interests of passengers. Those doubts have vanished. The Competition Commission will not issue its final report until August. But the Transport Secretary Ruth Kelly has lost no time in announcing a review of the economic regulation of the UK airport system. The BAA monopoly has, finally, run out of runway.