Boris Johnson has suggested building tunnels linking England and Ireland via the Isle of Man.

The UK prime minister’s plan has been ridiculed by many.

Under his proposals, Mr Johnson’s three tunnels would branch out from England and Scotland, arriving at a roundabout dubbed ’Douglas Junction’, before heading across the Irish Sea.

However, the UK press says that the idea is said to exist ’primarily in the mind of the PM’, according to one senior aide.

The idea comes amid talk of a 25-mile, £10bn, undersea tunnel described as the ’Boris Burrow,’ that would link Stranraer in Scotland and Larne in Northern Ireland.

Studies are currently being undertaken by the chairman of Network Rail, Peter Hendy, to find out if the 25-mile tunnel would be possible.

A direct tunnel from Stranraer to Larne would have to cross Beaufort’s Dyke -- where 1.5million tonnes of munitions were dumped after the Second World War.

Ordnance from there has ended up on Manx beaches on a number of occasions.

On Monday the Times reported that officials at Number 10 decided the 25-mile tunnel from Stanraer to Larne idea may be impractical.

Instead, officials have suggested three tunnels, starting from Stranraer, Liverpool and Heysham in Lancashire, could meet at a roundabout at the Isle of Man, before a tunnel stretched on to Larne.

The tunnels would be far longer than the Channel Tunnel.

The Daily Mail said that a ’source’ said: ’The No 10 policy unit is condemned to keep looking at this idea, which exists primarily in the mind of the PM.’

The idea comes just over a year since the Sunday Times suggested a similar scheme.

When the Isle of Man Examiner looked at the Sunday Times story, we discovered that it was based on flimsy evidence -a throwaway line from a representative of the British Tunnelling Society saying a tunnel between Liverpool and the Isle of Man would solve problems.

The Examiner read through the British Tunnelling Society’s workshop report quoted by the Sunday Times and discovered that it made no mention of the Isle of Man at all.

The lead author of a report published by the Institution of Civil Engineers Bill Grose then told the Examiner that he had been talking to the Sunday Times about future tunnelling projects.

’These are just concept ideas, based on speculating what tunnelled projects might be possible if the cost of construction can be significantly reduced and the technical difficulties of long tunnels (e.g. ventilation, safety, emergency escape) can be solved,’ he told the Examiner.

’I don’t know whether anyone has seriously considered it. You would know better than me.’