A fringe meeting at the Trade Union Congress has reveled a split among unions over Heathrow Airport's expansion.

Heathrow's controversial plans to build a third runway at the airport were given government approval in the National Policy Statement on airports, voted in by Parliament in June.

However at a fringe meeting at this year's Trade Union Congress, arranged by the No 3rd Runway Coalition, unions including the Public and Commercial Services Union (PCS) and the Transport Salaried Staffs’ Association (TSSA) spoke out to highlight their opposition to the scheme.

Heathrow has the support of a number of big trade unions, including Unite, GMB, Community and BALPA unions which support many of the 78,000 workers at the hub airport.

The majority of unions support the expansion at Heathrow

But PCS and TSSA unions have spoken out about environmental concerns linked to expansion as well as raising questions over the legitimacy of the economic predictions following expansion.

TSSA raised the decision to forge ahead with expansion despite the impact on air pollution and emissions as the transport sector "heading backwards".

Manuel Cortes, the union's general secretary also called on the government to link transport and energy policy in order to "help deliver a coordinated approach to delivering a low carbon economy."

The fringe meeting was held at the Trade Union Congress in Manchester

At the same meeting, Chris Baugh, Assistant General Secretary of PCS, cited a report the union commissioned by Roger Seifert, Professor of Industrial Relations and Human Resources Management with the University of Wolverhampton Business School.

The professor examined the bold claims made about the number of jobs that can be brought in to the area with an expanded Heathrow, which have been quoted as ranging from 30,000 to 180,000 at various times.

While the professor accepted that job creation was inevitable and valuable, he did report that the job figures were likely to be bloated estimates and that many of the jobs created would in fact be displaced from other companies and roles as well as other airports, as Heathrow would further its domination of the airport market in the UK.

He also reported that the overwhelming majority of jobs would be created by third party employers, therefore estimated are dependant on projections of the way companies behave.

Despite the dissent at the conference, the majority of larger unions representing employees at Heathrow still back the expansion project with is due to be completed by 2026.

A second consultation is expected to be launched by Heathrow in early 2019, before a fully finalised plan for the airport's growth will be submitted for development consent applications. Heathrow Airport Limited hopes to start construction by 2021.

However, a legal challenge by five councils including Hillingdon , as well as Sadiq Khan and Greenpeace has been filed against the decision taken to grant Heathrow consent to develop the third runway.

Paul Beckford of the No 3 Runway Coalition, said: " The role played by trade unions in helping the transition to a low carbon economy will be crucial. I

"t is clear that workers must be informed about the challenges and opportunities presented by this transition. A programme of robust engagement is vital to ensure that workers don’t feel that the choice being presented is one between their jobs and the environment.”

“The claims made by industry and government about the number and quality of jobs that will be delivered by expansion at Heathrow are highly questionable.

"The opposition to expansion by trade unions like PCS and the TSSA is extremely welcome and demonstrates that the movement remain rightly sceptical about the alleged economic benefits and concerned about the environment damage that would be caused.”