Overlooking the ever-expanding Tyne Tunnel 2 site, this strange telescopic structure, called Gasholder No1, is the ideal place to watch the construction work taking place.

Unless you work for Northern Gas Networks (NGN), though, it's not a view you'll be able to take in first hand as the site is closed to everybody but contractors.

Luckily for you, the Gazette managed to arrange a visit to the top of the 35ft holder, complete with still and video cameras, to put you in the picture.

The trip to the top was not for the squeamish or anyone lacking a head for heights, however.

Built in 1955 by Oxley Engineering, the 55m-diameter structure is classed as a medium-sized gas holder, although, when its three telescopic sections are raised, it can reach a dizzying 170ft.

Kevin Stephenson, 50, area operations manager for United Utilities, which maintains the site for NGN, said: "Scared of heights? No, not in the least. I have been doing this for years, and I have been on a few at their full heights. Some parts of maintenance activities require that you to be up there, but if it's too windy, you don't attempt to go up.

The father of two, from Wallsend, North Tyneside, explained why the holder isn't currently at its full height.

"It's so low at the moment because it's off-line in the summer," he said. "We don't need the storage capacity as people use less gas.

"It's a lot safer keeping the sections down than up in the air.

"It's due to come back on-line in October. In the winter, we need more capacity to provide enough gas over the peak periods, like at tea time.

"When the sections inflate, each one is sealed by water to stop the gas escaping from the holder."

He added: "I can't think of any better view of the new Tyne Tunnel project, unless you had a bird's-eye view from a helicopter."

"Having two tunnels will be a good thing. It's going to make the situation a lot better than it is at present.

"It's probably the best view on the Tyne when the tall ships race has been on."

Though he has been based mainly on the north side of the river, seeing to the diversion of high-pressure gas pipes to make way for the tunnel, it was clear Mr Stephenson enjoyed coming back to take in this fascinating vista.

And the best bit, he said, is yet to come. "The underwater bits they will do later in the year, that will be a sight to see," he said.

That will involve a huge barge dredging a trench along the bottom of the river, into which three interlocking sections will be placed, joined up, then pumped free of water.

By that time, the most challenging parts of the tunnel will have been finished, paving the way for its completion in December 2010.