LONDON — Prime Minister David Cameron is coming under intense pressure from business leaders and airlines to end years of deadlock and decide whether to expand London's overstretched Heathrow airport — something that will infuriate local voters and some members of his own party. The decision will affect 750,000 people living under Heathrow's busy west-London flight path who are worried about aircraft noise, pollution and safety. For Heathrow, the stakes are high. Without new runways and airports Britain risks turning into a global aviation also-ran as competition heats up from more attractive hubs in Europe. “The government must stop tiptoeing around on aviation because of short-term political considerations,” said John Longworth, director-general of the British Chambers of Commerce. “Unless politicians grasp the nettle and make some tough decisions, both our export and inward investment potential will suffer.” Heathrow is the world's third-busiest airport but it is close to full capacity. The government must decide whether to expand it or consider several other options such as building a new hub elsewhere in the London area. Under pressure from liberals and green groups, Cameron's Conservative-led coalition opposed building a third Heathrow runway after it came to power in 2010. It also ruled out expanding London's secondary airports at Gatwick and Stansted. Although the tens of thousands who work at Heathrow would disagree, the idea of another runway is unpopular with many local voters as it would increase the number of planes flying over the densely populated and leafy suburbs of western London. But with demand for air travel expected to more than double in Britain to 300 million passengers per year by 2030, speculation has been growing that Cameron could still go back to the Heathrow plan which he appears to favor. The debate heated up this month with the launch of a government-appointed commission to review all available options and finally decide what to do. It is already a hot issue for the next general election. Since the commission is not due to report until after the 2015 vote, observers believe that would give Cameron a chance to perform a U-turn and revert to the Heathrow expansion plan. Either way, the industry is frustrated. The lack of action has led the bosses of IAG's British Airways and Virgin Atlantic — normally the fiercest of rivals — to join forces to form the so-called “Aviation Foundation” to put pressure on the government. In a strongly worded report, former deputy prime minister Michael Heseltine criticized the government's aviation policy, saying it was holding back economic growth. “The world is increasingly competitive and we have to respond to that or we will slip gradually down the world's growth league tables,” he said. Both in government and among families living under Heathrow's flight path, emotions are running high. Plastic signs reading “No third runway” adorn the lamp posts of Harlington, a village on the edge of Heathrow where local activists have campaigned against expansion plans for a decade. — AP