Thousands of homeowners would lose huge sums on their homes under plans to turn Gatwick into the biggest airport in the world, it has been claimed.

The British Airports Authority (BAA), which wants to build a second runway and raise Gatwick's capacity to 90 million passengers a year by 2019, has provided compensation packages for householders who would be worst affected by increased noise.

But campaigners complained the schemes will help fewer than 300 families while 7,600 would be left out of pocket as the value of their homes collapses.

Under the proposals to extend Gatwick, the airport's boundaries would expand towards Crawley and dozens of houses to the south of the existing boundary would have to be removed.

Under its home owner support scheme BAA has promised it would work out how much the houses would have been worth without the expansion and pay their owners that amount.

The company has also launched a property market support bond, under which people worst affected by noise would have their homes purchased at the price they would have fetched without the runway.

Airport managing director Paul Griffiths said there was still uncertainty over whether the Government would decide to build an extra runway at Heathrow or Gatwick.

He said: "We appreciate this uncertainty causes a problem for property owners who may be affected by potential development.

"We have developed these voluntary schemes following consultation with our neighbours.

"We have looked at the suggestions, questions and concerns raised by our local communities and developed schemes we think are both fair and responsible and go some way to mitigating the impacts of living near Gatwick."

Brendon Sewill, chairman of the Gatwick Area Conservation Campaign, branded the compensation schemes "miserly" and said they would only affect the 280 homes worst affected by expansion.

He said: "People who would be severely affected by noise would be fully compensated but the area they are covering is extremely small. There are another 7,600 homes which would be affected by noise whose value would be reduced.

"People living in those houses won't be able to move without incurring a financial loss so their quality of life will be blighted."

Tim Lockwood, the airport's director of planning and environment, said BAA had worked out the compensation scheme using the same criteria used to measure compensation packages for the Channel Tunnel rail link and most road building projects.

He said: "We believe we have got it right."