Heathrow expansion is not just a flight of fancy for Scottish businesses

In an increasingly global economy, the international route network offered by Heathrow is crucial to Scotland's competitiveness. But with the UK's only hub airport now at 99 per cent capacity, an additional runway is urgently needed and would provide major economic benefits for Scotland and the rest of the UK.

Although we would all prefer more direct international flights from Scottish airports, Heathrow can offer long-haul direct air routes that Scottish airports cannot. This is essential both for Scottish firms seeking to access overseas markets and for attracting inward investment to our shores.

Heathrow's international route network is a national asset that is therefore every bit as important to Scotland's future as it is to London's.

But Heathrow has been left standing in the departure gate by its competitors: Charles de Gaulle has four runways, Schipol has five. Heathrow only has connections to 180 destinations worldwide, compared to 265 from Frankfurt.

Most worryingly, Heathrow's two runways are now effectively operating at full capacity, leading to regular delays and cancellations, particularly on domestic flights. The situation is set to get worse as in 2008 Heathrow should reach its planning and operational cap of 480,000 flights.

Continued capacity constraints at Heathrow will undoubtedly damage Scottish competitiveness for a number of reasons.

First, lack of runway capacity causes routine delays for passengers, with over half of arriving aircraft being held in stacks. This causes regular and unnecessary delays to connections from Scottish airports and affects the efficiency of our businesses. Stacking also increases pollution.

Secondly, lack of runway capacity means that small delays due to fog or strong winds can cause widespread disruption as there are no available slots into which delayed aircraft can be scheduled.

Thirdly, the number of routes served by Heathrow is declining as airlines use scarce remaining slots to concentrate on the most profitable routes, cutting off vital links to Scottish regions. The number of UK domestic routes served by Heathrow has more than halved from 21 to nine since 1990, and will drop to eight in April when the route to Inverness is stopped.

The pressure on landing slots at Heathrow will only increase with the introduction of the EU-USA "open skies" agreement next month, which liberalises transatlantic travel and allows any EU-based airline allowed to fly from any city within the EU to any city in the US, and vice versa.

This will lead to a further increase in international flights, with a consequent loss in less lucrative, domestic or short-haul services due to a lack of landing slots.

But even with a third runway, Heathrow will be at 70 per cent capacity by 2030, so government needs to look at how best it can protect access for less profitable routes from outlying parts of the UK so that we can all enjoy the economic benefits of its expansion.

There have been calls for domestic flights to be replaced by high-speed rail links, but rail is not a practical alternative for many Scottish destinations in the way it may be for Manchester or Liverpool. And rail links to the centre of London are certainly not an option for business travellers who want to connect to international flights.

Global air links are also vital to Scottish tourism – 87 per cent of international visitors arrive by air, spending more than 1.4bn every year.

Obviously, there are concerns about the environmental impact of a third runway, but the consultation document on adding capacity at Heathrow shows that growth can be achieved within environmental limits.

On climate change, aviation's emissions will be covered by the existing EU Emissions Trading Scheme long before a third runway is operational. If airlines want to fly more then they will have to pay for other industries to reduce their emissions.

This means that the overall amount of emissions in the atmosphere would not be allowed to increase as a result of a third runway at Heathrow.

We believe Heathrow is hugely important for the Scottish economy. It supports jobs and business – providing our main air links to many long-haul destinations. The case for growth at Heathrow is compelling and the government's consultation shows that it does not have to be at the expense of the environment.

For the sake of Scotland's and the UK's economy, we need to depart on the Heathrow expansion as quickly as possible.

Niall Stuart is press and government affairs manager at the Scottish Council for Development and Industry