LONDON - LONDON'S Heathrow would use extra capacity from a third runway to improve punctuality before introducing more flights, business leaders campaigning for expansion of the airport said on Monday.

Mr Colin Matthews, chief executive of Heathrow operator BAA , promised a smoother operation of the world's busiest international airport if the runway is approved, as well as a boost to the economy and a limited environmental impact.

The British government has said it will announce a decision on the disputed 9 billion pound (S$20.04 billion) expansion of Heathrow before the end of the month and its ruling could come this week.

Recent media reports have said the government is likely to back the plan, defying environmental groups angry at the demolition of around 700 properties, noise pollution over a larger part of west London and the broader issue of aviation's contribution to global warming.

'The first tranche of new capacity should be to improve Heathrow's reliability,' Mr Colin Matthews told reporters, adding that no new flights would be added until punctuality was up to an as-yet-unspecified level.

British Airways Chief Executive Willie Walsh added that an expansion of Heathrow was vital for future economic growth despite the downturn.

'There has (in the past) been a close correlation between GDP growth and air traffic growth. Everyone is (currently) focused on the short term, but everyone hopes for an upturn at some stage and it will be at least 10 years before there is a new runway at Heathrow,' he said.

Rail link
Heathrow, owned by Spanish giant Ferrovial , handles 65 million passengers a year and operates at 99 percent capacity over two runways.

Business leaders have repeatedly criticised the airport for its congestion, long queues at security and delays.

Capacity is capped at 480,000 flights a year, but this could eventually be expanded by a third if the new runway is added, BAA's Matthews said.

The expansion of Heathrow has been debated for years and is a highly emotive issue. The government has said it would only approve a third runway if environmental measures could be met.

These requirements could be met in part through investment in new high speed rail networks linking Heathrow with regions in the rest of Britain.

However, environmental campaigners were not mollified.

'We cannot carry on pouring money into the aviation industry. We really need to cut carbon emissions. We cannot expand Heathrow at a time of a global climate crisis,' said Ms Tamsin Omond, campaign leader of group Climate Rush. -- REUTERS