Work has begun at The Alnwick Garden in Northumberland on one of the world's largest tree houses.

With 6,000sq ft of buildings linked by 4,000sq ft of suspended satellite walkways, the 56ft high treehouse is costing £3.3m and will be able to withstand all weathers - including gale force winds.

Designed by John Harris, construction will take eight months and the tree house is due for completion by July 2004.

With the capacity to hold 300 people, it will consist of a multi-function restaurant and café area and education rooms offering a range of learning programmes and workshops including gardening, painting and cookery.

There will be partial disabled access to the suspended walkways and to the restaurant.

Trustee of The Alnwich Garden Trust, the Duchess of Northumberland, said: "The treehouse will appear as a 'hobbit-like' tree-top village rising above the forest floor.

"It is designed to provide a magical experience for children of all ages - and I suspect many adults too!

"People will be able to learn from, relax and enjoy the natural environment around them where they can lunch or take tea in the trees. I see it as an organic bio-friendly fairytale experience - providing a tremendous boost to the north's tourism offering."

A tree-based adventure playground area is also planned for The Alnwick Garden, which will include rope bridges, scramble nets, platforms and aerial walkways below the suspended tree house.

The scheme comes just a year after Prince Charles opened the first phase of The Alnwick Garden regeneration project, which has received public sector funding from The European Regional Development Fund and the Government Office North East, ONE NorthEast RDA and Northumberland Strategic Partnership, Northumberland District Council, Alnwick District Council and the Learning and Skills Council.

Although only a third of the garden is complete, it is set to have welcomed up to 550,000 visitors in 2003, despite original estimates of 67,000 a year.