An impression of what the bridge could look like.

The Institution of Civil Engineers (ICE) has produced an imaginative plan to physically link Northern Ireland to the rest of the UK.

But plans don't include a bridge. Instead, they favour the construction of a tunnel under the Irish Sea.

In fact, the plan is for two tunnels - one from England to the Isle of Man, and a second from the Isle of Man to Co Down.

They say their proposal would be better than a bridge, as a rail tunnel would not be at the mercy of bad weather, and would avoid the problems in spanning Beaufort Dyke, a deep sea trench in the North Channel containing a million tonnes of dumped wartime munitions.

The plan is part of a broader list of tunnel projects put forward by the society.

They include a tunnel from Hampshire to the Isle of Wight, another under the Bristol Channel between the West Country and Wales, and a new tunnel under the Thames.

Bill Grose, lead author of the ICE report, told the Sunday Times: "A tunnel starting north of Liverpool that surfaced in the Isle of Man and then went back under to reach Belfast would solve all the problems" he said.

"Tunnels are less prone to bad weather, and construction is getting faster and cheaper every year."

The distance from England to the Isle of Man is around 50 miles, and from the Isle of Man to Northern Ireland is just over 30 miles.

Mr Grose, a former chairman of the British Tunnelling Society, added: "As prices continue to fall, tunnels will become increasingly attractive as a way of connecting the United Kingdom.

"It cost about £50m per kilometre for a twin rail tunnel, but costs are falling. When we reduce them by another 50%, tunnelling will become popular and very long tunnels become feasible.

"Tunnels and bridges cost much the same - but tunnels are not prone to bad weather."

The ambitious proposals are surfacing as Prime Minister Boris Johnson is known to be interested in major construction projects to unite the UK in the post-Brexit era.

In September last year it was learned that Mr Johnson had asked Government officials for advice on the costs and risks of building a bridge from Scotland to Northern Ireland.

Initial estimates put the cost at around £15bn.

The worlds longest railway tunnel is the 35-mile St Gotthard Base tunnel under the Swiss Alps, which opened in 2016.

Belfast Telegraph