Protesters aim to bring Heathrow to a standstill with regular road blockades if ministers approve plans for expansion next month.

John Stewart, chairman of campaign group HACAN, told the Chronicle hitting the aviation industry in the pocket was the only way to force the Government into a re-think.

He said a new breed of middle-aged militant housewives were determined to make airport chiefs pay for a 'series of broken promises'.

"It's embarrassing enough for the Government when organisations like Plane Stupid climb onto the roof of the Commons," he said.

"But when it's a middle-aged housewife from Hounslow chaining herself to the fences of BA's offices that's a whole new ballgame."

He said the most popular plan was for activists to hold up traffic on the busiest roads around Heathrow by driving at a crawl.

Other possibilities include targeting BAA's headquarters in Bath Road or playing loud music outside key MPs' homes in the early hours, while invading Heathrow or boarding a plane remain last resorts.

"What could make life really awkward for both the aviation industry and the Government would be if either they or businesses began to lose money as a result of residents' actions," said Mr Stewart.

New transport secretary Geoff Hoon is expected to announce his long-awaited verdict before Christmas on plans to increase Heathrow's capacity by up to 50 per cent.

Mr Stewart is confident the 'neon light' options of a third runway and sixth terminal will be rejected following pressure from Labour MPs, who fear that could cost the party up to 12 seats at the next election.

Instead, he suspects the Government will try to 'sneak in' expansion through the back door by allowing mixed mode - meaning planes could take off and land from both runways throughout the day - within the current cap of 480,000 flights a year.

Mr Stewart insists that option would be 'disastrous' for Heathrow's neighbours, who would lose their 'much-valued' half day of peace.

But he remains confident the 'growing tide of opposition' to expansion means it will 'never see the light of day', whatever Mr Hoon announces next month.