Published: 10:14 AM October 8, 2018 Updated: 6:11 PM September 17, 2020

Boris Johnson offered bluster but little else during his conference set-piece - Credit: PA Wire/PA Images

A retired offshore engineer has succinctly taken down both Boris Johnson's Irish bridge proposal and his attempts to become prime minister in just four paragraphs.

Writing in the Sunday Times letters pages, James Duncan from Edinburgh points out the problems with building a bridge between Great Britain and Northern Ireland.

As well as pointing out the enormity of the project, he also highlights the amount of munitions and bombs that have been dumped in the water across the stretch by the Ministry of Defence after World War II.

Duncan says that 'no sane contractor or responsible government' would sanction the construction because of the complexity involved.

In a damning indictement of Johnson, he calls it a 'thoughtless soundbite' that is 'typical of Johnson'.

James Duncan's letter to the Sunday Times - Credit: Archant

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He signs off by claiming that 'he simply does not have the seriousness to lead the country.'

The full letter published by the newspaper can be found below.

'On your front page Boris Johnson airily proposes building a bridge from Britain to Northern Ireland. As a retired offshore engineer, I know this is about as feasible as building a bridge to the moon.

'Many long bridges have been built, but none across such a wide, deep and stormy stretch of water. For a great part of the 22-mile route the water is more than 1,000ft deep. It would require about 30 support towers at least 1,400ft high to carry the road deck across the deepest part and above the shipping channel. In total the bridge would require 54 towers, of heights never achieved anywhere in the world.

'In addition, the trickiest section, Beaufort Dyke, was used for many years from 1946 to dump obsolete munitions. The Ministry of Defence estimates the total dumped at more than 1.5m tons. There are no maps of their locations.

'No sane contractor or responsible government would consider building such a bridge, and because of the weather conditions it would probably have to be closed for considerable periods if it did. The proposal is just another thoughtless soundbite. This is typical of Johnson. He simply does not have the seriousness to lead the country.'