Special report by Brian Gomm: OVER 200 years ago ironmaster Abraham Darby the Third made a giant step forward in the world of construction when he spanned the River Severn with his Iron Bridge.

This remarkable feat of 18th century engineering was highlighted recently on television in a documentary. The programme depicted 21st century engineers' struggle to make and erect a model of the bridge.

Darby's 378 ton cast iron creation revolutionised civil engineering and as those who witnessed the efforts of modern man to build a half-size replica with the benefit of hindsight and theories can only add to the admiration for the ability of Darby and his men way back in 1779.

A few weeks ago the Journal related the intriguing story about how Atherton foundryman Harry Hodson had built a unique four feet long scale model of the bridge -- currently on show at Coalbrookdale.

Mr Hodson, who cast his scale model in aluminium in the 1980s with the help of staff and pupils at Tyldesley Fred Longworth High School, featured in a BBC 2 documentary Mystery of the Iron Bridge along with Bolton's larger-than-life industrial heritage guru Fred Dibnah.

To say Mr Hodson knows about the Iron Bridge is an understatement. His interest in the ground-breaking construction stemmed from a real fisherman's tale.

While on fishing trips to the Iron Bridge stretch of the River Severn with Tyldesley Anglers Association a teenage Mr Hodson was intrigued by the structure which opened in the summer of 1779 having cost just over £6,000 to build -- including £15 for free beer with which to celebrate the completion!

Mr Hodson's angling mate, Bert Pendlebury, used to look up at the majestic bridge and tease -- "Call yourselves engineers, you men couldn't build that today!"

Harry Hodson rose to the challenge and devoted himself to building an exact replica of the real thing, much of which was spent in his garden shed workshop in Tyldesley Road. He soon knew every inch of the 1400 parts of the bridge and spent years filing the multitude of dovetail joints which hold the construction together.

Having spanned the Severn for four centuries the bridge is still the centre of controversy. Mr Hodson believes it most likely that the largest parts of the bridge (the main arch castings were 70 feet long) were cast at the Coalbrookdale upper works and conveyed downstream.

But there are those who claim the work was done near the bridge site -- but many reckon the 378 tons of iron needed to construct the bridge came from the Coalbrookdale upper works and the main ribs were transported downstream by barge.

But the theory put forward on the TV documentary -- and put in to practice on a half-size bridge on screen -- that simple pole and rope scaffolding was used to erect the bridge in 1779 is contrary to Mr Hodson's idea backed by around 45 years of painstaking research into the subject of the Iron Bridge.

He has also spent a working lifetime of practical involvement with spells at local foundries such as Grundy's in Tyldesley, Greenhalgh's at Atherton and Beloit Walmsley engineering works in Bolton and is a contributor to engineering publications.

He says: "I hope those Journal readers who saw 'The Mystery of the Iron Bridge' on BBC2 enjoyed the programme. "On the other hand, I hope they were not misled into thinking that the real Iron Bridge was built using flimsy pieces of timber for the scaffold.

"Viewers saw the Royal Engineers erect two main pillars and two half-ribs of a replica bridge -- the same identical parts on the real bridge are twice the length and six times heavier.

"Regarding the Elias Martin picture, which seemed to cause considerable excitement among a few people, it was discovered in Sweden in about 1995 and may well be a genuine record of the Iron Bridge under construction, although there is no exact proof of this.

"The picture shows a simple wooden scaffold supporting the partly built bridge, also there is notable absence of lifting equipment, ropes and chains etc. There is a possibility that the scaffold may have been much larger and stronger, previous to the time when the artist first saw it, if not, then I am confident it would need to be further improved to carry out the next stage of the bridge construction.

"However, what led to the discovery of the Elias Martin painting? From 1992 onwards I published a 'conjectural account' of the construction of the Iron Bridge.

"The article, which included a photograph of a painting by Culcheth artist Harry Stirrup, was circulated in some European Countries, Sweden among them. In view of this, it seems to be a remarkable coincidence that the Elias Martin painting should suddenly come onto the scene after an absence of 200 years.

"My publishers, Steel Times International, are presently investigating a possible connection between the two paintings."