Families face a drop of at least £25,000 in the value of their homes if they are edged outside a top school's catchment area.

Education officials want to draw up new boundaries to limit the number of parents trying to send their children to Thomas A'Becket Middle School, Worthing.

But a leading Worthing estate agent warned householders who find themselves outside the revised boundary: "It will hit you in the pocket."

West Sussex County Council is currently quizzing families over the controversial plans, which were drawn up after the school in Glebeside Avenue, Tarring, was repeatedly oversubscribed.

In its last Ofsted report in 2003, Thomas A'Becket was described as "a very good school which provided a stimulating learning environment for all its pupils".

But it also warned that the school, which caters for 800 pupils in 25 classes, was well above the average size.

Families specifically moved to the catchment area so their children could go to the school, boosting house prices by between ten and 15 per cent.

Ian Ward, a partner at Symonds Reading estate agents, in Chatsworth Road, Worthing, said a three-bed semi inside the area was worth on average £25,000 more than similar homes outside the area.

The Argus has been told some families who face exclusion are planning to sell up and take on bigger mortgages to move back inside the proposed new boundary.

In a letter to parents, Helen Moules, pupil admissions manager for the county council, said: "In 2005, pupil numbers in the catchment area have increased more than anyone could have forseen.

"This was largely due to people moving into the catchment area, which is a popular residential part of Worthing."

She said it was proposed to place the area to the west of Lindum Road and Princess Avenue into the catchment area of Orchards Middle School. People living to the east of Clifton Road and Crescent Road/West Buildings would go into the Chesswood Middle School catchment