Prince Charles arrived at Orcombe Point, near Exmouth, Devon, in his helicopter on 3 October to see the \'Geoneedle\' that marks the World Heritage Site of the Dorset and Devon coast. The day before it was still surrounded by scaffolding and being finished off by the Portland-based masons of St Blaise.

Devon County Council had only approached St Blaise five weeks earlier with a design by artist Michael Fairfax that had the 5m high obelisk constructed from blocks of Capton Red sandstone, White Lias, Blue Lias, Ham Hill, Forest Marble, Portland, Purbeck and Beer stones - the major building stones produced in the area of this World Heritage Site between Orcombe Point and Studland Bay.

The design and construction of the geoneedle had suddenly become urgent in order to fit in with Prince Charles\' schedule after he agreed to come and announce its presence.

The council contacted Michael Fairfax because he is the town artist for Exmouth, retained by the council. He also works for several other councils and has produced many municipal works of art since he set himself up as a public artist in 1980.

Dave Collier, the masonry manager at St Blaise, had to point out that actually making the obelisk out of blocks of the various stones would not be possible in the timescale and in any case he doubted the wisdom of combining limestone and sandstone in the salty coastal environment.

He suggested instead that the \'needle\', which is 1m square at the base and goes up to a stainless steel point, be made of Portland stone and that squares of the other stones be inset. The idea was accepted.

Hanson Bath & Portland cut the Portland stone for St Blaise using three different beds. The bottom two stones are Basebed, the next three Whitbed and the top three Roach. Quarries from which the other stones came supplied whatever they had to hand and Weymouth College\'s masonry department sawed them.

The Purbeck was supplied polished, which everyone decided made a pleasing contrast to the honed finishes of the rest of the stones. All the stones were donated by the quarries.

The insets were cut to squares of 25mm thick, tapering from 300mm wide at the bottom to 60mm at the top. They appear in the \'needle\' in the correct geological order, with the oldest at the bottom.

Dave Collier only decided two days before Prince Charles\' visit that there would be time to fit the inserts.

The two masons who worked on site throughout the project set about cutting the indents while Collier rushed around with the stone that he had arranged with Chris Daniels at Weymouth College to process to the dimensions provided.

The indents are fixed in place with stainless steel dowels and resin and are lime mortared.

St Blaise also had to cut an indent to accommodate a stainless steel plaque, which in fact turned out to be 2mm smaller than the dimensions they had been given, although that should at least accommodate any difference in movement when the sun shines.

The stainless steel tip that the artist wanted to reflect the sun, the sky and the sea to bring all the elements of the coastline together in the obelisk, was fitted to the top two stones upsidedown. A steel bar goes through the stones to secure the pinnacle and the assembly was tipped up on to the top of the pyramid of stone on the scaffolding.

As the steel top is in a high and exposed place it had been decided to put a lightning conductor through the middle of the obelisk, which had meant drilling a hole through all the stones before they were laid.

When the project started, says Collier, the first stone arrived before the scaffolding. But because time was short, they fixed it straight off the Hyab on the delivery lorry.

The site of the obelisk is 700m from the road and Collier admits there was an element of luck with the weather. "The two weeks we were on site were bright and dry," he says. "If it had rained we wouldn\'t have been able to get the stone on site."

The two masons building the obelsik did not even leave the site during the project. Next to it is a council campsite and the masons stayed there for the fortnight that the obelisk was being erected . "The lady who supervises the site lent them duvets," says Collier.

All concerned seemed delighted with the result. Prince Charles said how splendid the Geoneedle had looked as he arrived in his helicopter. Only the artist had some reservations. "I think I would probably want it bigger," he told NSS. "If it could have gone up to 20m it would have been really exciting."

There are now some suggestions that there should be a number of such Geoneedles along the World Heritage coastline."