Hounslow Council has been accused of "backtracking" on its opposition to expansion of Heathrow Airport after opting not to support a major rally.

London mayoral hopeful Zac Goldsmith and the newly appointed shadow secretary John McDonnell, who is MP for Hayes and Harlington, are among those expected to speak in Parliament Square on October 10 at the protest against a third runway at the airport.

The anti-expansion campaign group HACAN, which is organising the demonstration, said it had the official backing of Wandsworth, Hillingdon, Richmond, Kingston and Windsor and Maidenhead councils, and was also being supported by Hammersmith & Fulham Council.

Speaking at a borough council meeting on Tuesday, Councillor Peter Thompson, leader of Hounslow Conservative Group, said: "Residents have received notification of the rally in Westminster and have noticed the absence of Hounslow Council from those organisations giving their support.

"Perhaps they're wondering if the council is backtracking on the leading role it used to have in actively opposing Heathrow expansion."

Councillor Amrit Mann, deputy leader of the Labour-run council, insisted the council's stance on Heathrow had not changed and restated its mantra of "a better, not bigger, Heathrow".

"Our position remains that we are engaging with Heathrow for them to service our residents with the mitigating factors they are required to deliver," he said.

"We can only do that through negotiation. Our position of 'better not bigger' remains but this is why we are not participating in the rally."

Hounslow Council confirmed in July it had been working with Heathrow on plans for a 9,000-home "garden city" in the borough, but council leader Councillor Steve Curran insisted at the time this was not dependant on a third runway being built.

The Airports Commission has recommended a third runway should be built at Heathrow, rather than adding a second landing strip at Gatwick Airport, but only if certain conditions are met, including an end to night flights.

The government has yet to respond in full to the commission's report, which was published on July 1.