The Airports Commission is due to issue its interim report and there are claims it will recommend additional runways

Veterans of the last Heathrow protests are drawing up plans for imminent action after claims that the Airports Commission will recommend additional runways at Britain's biggest airport.

The commission is due to issue its interim report on Tuesday with a shortlist of options for runways in the south-east, in advance of its final recommendations after the general election.

But claims that a draft shortlist pointed to Heathrow as the most likely candidate for expansion have infuriated some Tory MPs and put campaigners on high alert for a new battle, even if other options should remain on the final shortlist. Campaigners warn that Sir Howard Davies , the commission's chair, may become a protest target.

John Stewart, who chaired the coalition of opponents that succeeded in overturning Heathrow expansion at the end of the last decade, and works closely with the airport on community measures, said: "Davies has lost credibility – possibily through no fault of his own. I think Davies and the commission will now be targeted.

"He won't be able to hide away any longer. He will be seen by many campaigners as promoting expansion at Heathrow, and as being in the pro-Heathrow camp."

While the timetable for the commission was widely seen as kicking the question of airport expansion into the long grass, the impending publication of the interim report has unexpectedly thrust Heathrow back into the spotlight for the reluctant Conservative hierarchy and activists.

Leo Murray of Plane Stupid said: "The campaign was mothballed when the government came in, and the commission meant it wasn't on the agenda. Now we're dusting off the D-locks" – a reference to the bicycle locks used by protesters to stop police moving them.

Other environmental campaigners warned that the case for building new airport capacity to meet business travel demand did not stack up. WWF said that despite an improvement in the economy, business flights have not picked up from a decline lasting more than a decade.

The green group said Civil Aviation Authority figures show business air travel down 13% since 2000, and as much as 23% down at Heathrow, despite a modest recovery since the financial crisis of 2008-09.

Jean Leston, transport policy manager of WWF-UK, said: "We're being sold airport expansion under false pretences. Heathrow's growth projections simply don't match the reality."

Transport secretary Patrick McLoughlin said the Conservatives would not be betraying voters if a third runway were built. Tory MP Zac Goldsmith said on Friday that any decision from the prime minister to back Heathrow expansion would represent an "off-the-scale betrayal".

But McLoughlin said people were obsessing over Heathrow and should "wait and see what the commission say in the longer term", adding that David Cameron's pledge was not to build a third runway "in this parliament" and any decision would come after 2015.