Boris Johnson reportedly considering building a bridge between Scotland and Northern Ireland

It is seen by some Brexit supporters as a way around placing an alternative border in the Irish Sea.

Channel 4 News have reported that they have seen documents that reveal that the UK's Treasury and Department for Transport have been asked for advice on possible costs and risks.

This is not the first time that Boris Johnson has suggested such an action, as almost a year ago to the day, back when he had just resigned as Foreign Secretary, he told, and asked, The Sunday Times "What we need to do is build a bridge between our islands. Why don’t we? Why don’t we?"

It is believed by some Brexit supporters that this bridge could be a solution to the current impasse, which would remove the need for a border in the Irish Sea.

Back then, this "Brexit Bridge" was estimated to cost around £15 billion (€16.8 billion).

However, the latest report indicates that the price is still very much up in the air, as Johnson has reportedly asked specifically "Where this money could come from?" and "the risks around the project", which apparently include "WW2 munitions in the Irish Sea".

A UK government spokesperson told Channel 4 News that the "Government regularly commissions work to examine the feasibility of projects. During the leadership campaign candidates spoke about a number of issues which resulted in Number 10 commissions ahead of a new Prime Minister taking over.

"This PM has made no secret of his support for infrastructure projects that increase connectivity for people and particularly those that strengthen the Union."