Bosses at Birmingham Airport have reiterated their support for High-Speed 2, against claims from the Taxpayer's Alliance that there is no business case. In fact, all of the business case assumptions have been clearly set out. The idea that the risks are all downside is wrong: with a 60-year asset life assumption, DfT assume that all demand growth stops just eight years after opening: a balanced, but certainly conservative assumption.

High-Speed 2 represents an opportunity to further realise the potential of existing airports to ease the burden of constrained capacity at Heathrow. Indeed, London Mayor, Boris Johnson, recently cited the growing problem of limited capacity in and around the capital and called for boldness in addressing the issue. One of the proposed solutions is tapping into the vast potential of Birmingham as an alternative to airports in the south-east, which would be even more advantageous when Birmingham Airport is linked to High-Speed Rail.

Birmingham Airport (amongst other major regional airports) is a Strategic National Asset which, with emerging Government thinking, can easily form part of the solution to the over-heated south-east. There is spare capacity at Birmingham - enough capacity to take another nine million passengers immediately - and more than another 21 million passengers in future years, as it improves its capability with a modest runway extension, for which planning consent has already been given.

This spare capacity, allied with High-Speed 2, which will bring Birmingham within 38 minutes of the capital - or position Birmingham in 'Zone 4' of the Underground map - negates the need for further expansion elsewhere. Significantly, the Mayor singled out the future connectivity of the Midlands as a key factor in meeting the growing demand for aviation.

John Morris, Birmingham Airport's Head of Government and Industry Affairs, said, "The Government has already decided against airport expansion elsewhere and has indicated that existing spare capacity should be utilised. A more efficient use of regional airports, linked to High-Speed Rail, will ensure that opportunities are created across the UK, rather than draw jobs out of the regions and deliver them to the south-east.

"Aviation has its part to play in an integrated transport system, and High-Speed Rail must play a part in distributing the demand for international gateways, to airports that have capacity. Existing rail is reaching its limitations - both in speed and capacity - and in my view, experience with HS1 and the West Coast Upgrade, suggests that building new is better and cheaper than bodging up 150-year-old infrastructure. The West Coast upgrade delivered a 1970's-style 125mph railway; UK Plc now needs to invest in transport for the 21st Century.

"Birmingham Airport is a vital, yet underused piece of national strategic infrastructure. HS2 will help Birmingham and other airports in a similar position to take pressure off the overcrowded south-east, in the same way that Crossrail is relieving pressure within London".