After four years of planning, including an internet search for sponsors, work began on Monday on the first phase of a new garden at the ancestral home of the Duke of Northumberland .

The aim is to create a garden for the 21st century: a classically-designed garden enhanced by spectacular cascade waterworks which have never been seen before in this country.

The first phase - incorporating what used to be Alnwick Castle's Elizabethan walled garden, a new rose garden and a grand water cascade - will cost �5m.

The Duchess of Northumberland says the project will create jobs in the North East and will become a visitor attraction for the area.

The new garden, designed by Belgian garden architects Jacques and Peter Wirtz, will complement the riverside setting of the castle, whose grounds were landscaped in the 19th century by Capability Brown.

The centrepiece will be a huge water cascade, to be built by pumping specialists from Rochdale, Greater Manchester.

According to their brief, the tiered waterworks will be made to "dance and sing" with cascades, jets and fountains producing fascinating visual effects.

The aim is that the biggest garden project undertaken this century will become an educational venue before it opens at the end of 2001.

Viewing platforms are to be constructed so the development of the gardens can be monitored by gardening enthusiasts.

The historical seat of the famous Percy landowning family will offer an intriguing garden of poisons, a scented garden for the blind with braille notices, an interactive water maze and a working fruit and vegetable garden.

The project team, boasting the support of the Prince of Wales, is searching for more sponsorship for phase two, which will cost �9m.

Sponsors from Europe and the United States will again be sought out using the internet and the castle's own website to attract.