Five Mayoral candidates vying for Boris Johnson's job, big name MPs and national organisations will address the "biggest ever" rally against Heathrow's third runway.

Mayoral candidates from the main political parties will speak at the mass rally which will take place in Parliament Square, opposite the Houses of Parliament, in Westminster, on Saturday (October 10).

They will be joined by Hayes & Harlington MP John McDonnell, as well as a long-standing resident from the Heathrow villages who will lose her home if expansion goes ahead, and leading environmental organisations, such as Greenpeace and Friends of the Earth.

John Stewart, chair of HACAN, the campaign group opposing the third runway and one of the main organisers of the rally, said: “Thousands are expected to send a clear message to the Prime Minister that they will fight any decision to give the green light to a new runway at Heathrow.

“And the message from all the key Mayoral candidates is equally clear. They stand united on this issue. They are all firmly against a third runway.”

Bryan Tomlinson, of Stop Heathrow Expansion, is urging those against the runway to make their stand and “be heard” this Saturday.

He said: "The Government may ignore public opinion and try to force Heathrow expansion on the people of London and the South East. We all need to remind Parliament that they for us and not tax avoiding offshore investors.

“We already suffer illegal levels of air pollution and more people are affected by excessive Heathrow noise than all comparable airports in Europe put together.

“We have to leave a planet fit for our children and future generations to live free from deadly air pollution and overflown by 260,000 extra flights which is a disaster waiting to happen"

“Please join us at Parliament Square this Saturday at 11am.”

The rally, which organisers believe will be the "biggest ever" against Heathrow expansion, will take place just weeks before David Cameron is expected to make an announcement on a new runway for London and the South East.

At present, the Cabinet is looking at the recommendation of the Airports Commission that the runway should be built at Heathrow.

However, over recent months, the owners of Gatwick have continued to make the case for a second runway at their airport.

The rally, which is not intended to be a march so it is suitable for all ages, will begin at 10.30am. The speakers will address the rally at 11am to be finished by 12.30pm.

The full list of speakers is confirmed as:

  • John Stewart, Chair HACAN (to welcome and introduce)
  • John McDonnell, Labour MP for Hayes & Harlington
  • Zac Goldsmith, MP for Richmond & North Kingston (and Conservative Mayoral candidate)
  • Sadiq Khan, MP for Tooting (and Labour Mayoral candidate)
  • Sian Berry, Green Party Mayoral Candidate
  • Caroline Pidgeon, Liberal Democrat Mayoral Candidate
  • Peter Whittle, UKIP Mayoral candidate
  • John Sauven, Chief executive of Greenpeace
  • Gina Parihar, Head of legal at Friends of the Earth
  • Tania Mathias, Conservative MP for Twickenham
  • A long-standing resident from the Heathrow villages who faces losing her home