A government review is expect to recommend a feasibility study into proposals to build a tunnel connecting Great Britain and Northern Ireland.
Though widely derided, the idea of a tunnel - or 'Boris Burrow' - has recently been mooted as a way of ensuring the union is connected post-Brexit. PM Boris Johnson previously threw his backing behind the idea of a 'Boris Bridge' connecting the two islands.
The Telegraph has now reported that the Union Connectivity Review conducted by Sir Peter Hendy, the chairman of Network Rail, is expected to formally examine proposals for a fixed linked. The interim report is understood to call on experts to evaluate what the best link would be, a bridge or a tunnel.
Sir Peter is expected to have turned down plans for a bridge due to bad weather potentially closing it for around four months each year, the newspaper reports.
A spokesperson for Sir Peter said he would be advising on how connected all four UK nations "whether it is better rail services, new stations, air links for remote communities, or improving the state of our roads".
One factor which could put paid to any plans for a tunnel that has been raised on several occasions recently is Beaufort's Dyke, an area of the Irish Sea where surplus munitions from the two World Wars and radioactive waste were dumped.
It is believed that more than a million tonnes of munitions dumped there by the War Office and its successor the Ministry of Defence up until the mid-1970s.
The UK and Ireland Nuclear Free Local Authorities campaign group said it would be a "real challenge" to develop either a bridge or tunnel project between NI and GB, particularly if built over the dyke.
A leading bomb disposal expert branded both projects "impractical but not impossible".
Former Royal Navy clearance diver Michael Fellows told the Belfast Telegraph earlier this month that a tunnel under the Irish Sea would be a "dodgy operation" considering the amount of explosives on the seabed.
"Whatever you put in place, be it a tunnel or a bridge, it's going to need supports, so you're going to have to be very careful where you place those supports so that you don't hit something while drilling. You'll also have to conduct regular surveys to stop any explosions," he said.
"The idea of a connection between Scotland and Northern Ireland is a brilliant one but you have got to get rid of the explosive problem initially, which is an almost impossible task."
Northern Ireland Premium
Boris Johnson's plan to build three tunnels under the Irish Sea, with a roundabout underneath the Isle of Man, has put an end to any serious discussion about a road or rail crossing to Northern Ireland, according to one of the UK's leading architects.