Public support for the Fair Tax on Flying campaign is expected to top 100,000 this week as work begins on a study of the full impact of Air Passenger Duty (APD), commissioned by airlines which have lost patience with the government.

The Fair Tax on Flying coalition’s call for supporters to write to MPs demanding a Treasury review of APD has proved an unprecedented success since its launch two months ago.

The coalition includes Abta, Tui Travel, Thomas Cook, British Airways, Virgin Atlantic, easyJet, and a host of travel industry and business groups.

However, BA parent IAG, Virgin Atlantic, easyJet and Ryanair also have their own Axe the Tax group, fronted by the four chief executives, and have commissioned their own study of the economic impact by auditor and consultancy PwC.

The three UK carriers support the latest campaign – indeed, the backing of Virgin president Richard Branson has been key in taking support near to the 100,000 mark.

But privately the airlines believe the Treasury is unlikely to bow to the demand to examine the economic impact of APD, so they are paying for their own study.

An airline source confirmed to Travel Weekly that the study is underway and will be completed this autumn. The carriers intend to use the result to apply pressure on and potentially embarrass the Treasury leading up to the Chancellor’s autumn statement.

Seventy-five MPs of all parties have signed a petition demanding an ‘early day motion’ (EDM) in Parliament to discuss an economic review of APD.