THE world-famous aqueduct at Pontcysyllte, near Llangollen, has reopened to boat traffic.

The world's oldest, longest and highest cast iron aqueduct still in use has been the subject of a two-year programme of restoration, costing £2.15m, by British Waterways. The colossal structure, which crosses the Dee Valley at a height of 126 feet, was designed and built by engineers Thomas Telford and William Jessop between 1802 and 1805.

The aqueduct is Grade 1 listed, a scheduled ancient monument, and is also a candidate for World Heritage status. Still used for its original purpose, it sees the passage of more than 1,000 boats and 25,000 pedestrians each year.

The cast iron trough, which holds one and a half million litres of water, is 11ft wide, 5ft 3in deep and 1,007ft long and the aqueduct has 19 arches each with a 45ft span. The project originally cost £45,000 and 8,000 people attended the opening ceremony in November, 1805.

Robin Evans, chief executive of British Waterways, said: 'Pontcysyllte Aqueduct is truly awe-inspiring and a triumph of the Industrial Revolution. We are delighted to have completed restoration works and improvements for visitors in readiness for its 200th birthday celebrations next year.

'One of the Seven Wonders of the Waterways, this world-famous aqueduct is one of 3,000 listed structures on our 2,000-mile inland waterway network, which is visited by 10 million people each year. We are passionate about caring for these national treasures for the benefit of all across the country, and we want to encourage more people to visit our canals and rivers to enjoy their unique blend of heritage, wildlife and leisure benefits.

'Every winter we carry out restoration and maintenance, keeping our waterways safe and accessible, creating jobs and safeguarding our wonderful built and natural heritage.'

The aqueduct was drained last November with permission from Cadw, the historic monument agency, to allow the extensive works to take place. These included mechanically wire-brushing the entire cast iron surface and repainting to protect from rusting. Repairs were made to the masonry and cast iron metal work, and a hard-wearing towpath surface was laid and the handrail refurbished.

Although the aqueduct is open for boat traffic, the towpath and the Trevor Basin area at the northern end of Pontcysyllte are still not finished. A spokesman for British Waterways was unable to give a specific date for the opening of these areas.