Flights could cost an additional £50 if a new runway goes ahead at Gatwick, campaigners have warned.

Research published this week by the Aviation Environment Federation examined who would pay for a new runway at Gatwick or Heathrow. It found a new runway at Gatwick would mean an increase in airport charges per passenger from £8 at present to £33.60 – an increase of £25 per flight, or £50 combined with the return flight.

At Heathrow the increase would be from £19 per passenger to £31 for a single flight. Brendon Sewill, of the Aviation Environment Federation, said: “Gatwick Airport often claims that a new runway at Gatwick would be cheaper than one at Heathrow. But what they do not mention is that the cost would need to be borne by roughly half as many passengers.”

The report calculations are based on the estimate made by the Airports Commission that a new Gatwick runway would cost £10 - £13 billion. The study was written by former Treasury adviser Brendon Sewill, chairman of the Gatwick Area Conservation Campaign.

In the article, it is asserted that “a new runway at Gatwick would mean an increase in airport charges per passenger from £8 at present to £33.60 – an increase of £25 per flight, or £50 combined with the return flight.”

The figures were challenged by Gatwick bosses who said the calculations were "simply not correct".

A spokesman said: "As has been stated previously – and repeatedly – the cost of building the second runway at Gatwick is £7.8 billion.

"While airport charges are already comparatively low at £9, the increase that would enable the runway to be built is also low.

"We estimate charges to increase to a range of £12 to £15 in the long-term.

"This is possible due to the scheme’s low cost, low delivery risk, and phased delivery programme."