Speculation is increasing that the UK flight regulator, the Civil Aviation Authority (CAA), may be considering moves to take the low cost airline Ryanair under its wing.

Currently Ryanair is established as an Irish carrier, and is regulated by the Irish Aviation Authority. Changing the airline's status to bring it under the auspices of the CAA would allow the UK regulator to manage Ryanair's operations including crew training and maintenance.

At a recent after dinner speech Michael O'Leary, Ryanair's Chief Executive, seemed to acknowledge the discrepancy describing both Easyjet and Ryanair as UK based. European regulations state that a country can only issue an operating licence for an airline if its "principal base" is within that country.

Ireland issues Ryanair's operating licence, but its UK operations are considerably larger than those from Ireland. It would appear that the its largest base is Stansted Airport from where it flies to 89 destinations, compared to just 52 from Dublin where it is currently headquartered.

Sources from the CAA told the Guardian this week that "the time is rapidly approaching when we need to look at what is meant by 'substantially established' in the UK in a legal sense".

Moving the regulatory responsibility to the CAA would allow the authority greater scope to investigate allegations against the airline, such as those recently made by the Channel 4 Dispatches programme, Ryanair Caught Napping.