PM's study into Scotland-Northern Ireland bridge cost nearly £900,000
The report eventually concluded a connection between Portpatrick and Larne wouldn't be feasible
Nearly £900,000 of taxpayers' money was spent on a study commissioned by Boris Johnson which found it would be too expensive to build a bridge or tunnel between Scotland and Northern Ireland.
The Department for Transport said the research into the feasibility of a fixed link cost £896,681.
Network Rail chairman Sir Peter Hendy led the investigation, which found that a bridge would cost £335 billion, while a tunnel would require a budget of around £209 billion.
His report concluded that the project "would be impossible to justify" as "the benefits could not possibly outweigh the costs".
The Scottish Government’s Transport Secretary Michael Matheson told MFR News he could have saved the Prime Minister some money: “There was never going to be a bridge built across to Northern Ireland, for a whole range of reasons.
“This is just an example, again, of UK Ministers trying to come up with ideas, trying to encroach into areas that are devolved responsibilities, and quite literally making a mess of it.”
In addition to the huge expense, the inquiry also noted that the necessary work would be incredibly challenging.
The report described how Beaufort's Dyke - an underwater trench on the most direct route between Scotland and Northern Ireland - would need to be "carefully surveyed" due to a million tons of unexploded munitions being dumped there between the First World War and the 1970s.
Mr Johnson previously talked up the creation of a fixed link but accepted the conclusion of the report.
The research was carried out alongside a wider review of connectivity in the UK, which cost £1,102,525.
The DfT said the total of £1,999,206 for both studies was the amount spent on consultancy fees and department staff costs.
Sir Peter led the review alongside his role at Network Rail, and did not receive additional pay.
Willie Rennie, economy spokesman for the Scottish Liberal Democrats, said: "This is a gobsmacking sum to have spent on a PR stunt. It sounds like something that the Prime Minister came up with at 2am at a Downing Street party."
He added: "This is money that could have been spent on health, education and support for businesses. This bridge stunt is yet another example of Boris Johnson having fun at the expense of the taxpayer. He's totally unfit to be Prime Minister and should step aside."