The Dublin Airport Authority (DAA) is set to net £210 million (€302.5 million) from the sale this week of its 24.125 per cent stake in Birmingham airport.

The transaction is expected to close in the coming days, having being announced on May 17th, subject to certain conditions.

It is understood the seven district councils in the west midlands which jointly own 49 per cent of Birmingham Airport Holdings Ltd have decided not to exercise their pre-emption rights on the stakes held by the DAA and Australian investment firm Macquarie Airports Group.

This has paved the way for the sale to be finalised.

The DAA and Macquarie are selling their 48.2 per cent stake in Birmingham for £420 million to Airport Group Investments, a consortium comprising the Ontario Teachers' Pension Plan Board in Canada and the Melbourne-based Victorian Funds Management Corporation. The proceeds will be evenly split between DAA and Macquarie.

This windfall marks a substantial gain for the DAA, which took a stake in Birmingham in 1997 and then topped it up in 2000.

In total, the Irish airport manager spent about €34 million acquiring its shareholding. It is understood it has received at least that much back in dividend payments from Birmingham in the intervening period.

The DAA is expected to use the windfall to help fund its €2 billion, 10-year redevelopment plan for Dublin airport, which includes a second runway and the construction of Terminal 2.

Birmingham is the UK's fifth-biggest airport, handling more than nine million passengers a year. It was opened in 1939 and privatised a decade ago.

It is currently used by 50 airlines.

The DAA's only remaining overseas equity holding is now in Dusseldorf airport, where it has a 20 per cent stake.

Separately, the DAA said yesterday that 2.4 million passengers passed through Dublin airport in August, a 9 per cent year-on-year increase.

More than 15.7 million passengers travelled through the airport from January to August, a 10 per cent rise over the same period last year.