Claims that Metro North will provide a return of around €2 for every €1 invested do not stand up to scrutiny, and it is in fact unlikely to break even, according to a new economic study endorsed by An Taisce.

The analysis, by former OECD economist Matthew Harley, also states that the Railway Procurement Agency's recently released updated business case for the project failed to examine "very low capital cost" alternatives, such as a bus rapid transit system, using the port tunnel and M1 to serve Dublin airport and Swords.

Harley, who represented An Taisce in the recent Metro North oral hearings, claims the proposal has been subject to the "selective release" of information and results that are "favourable" to those who want it to proceed.

"The only rationale for this selective release is propaganda," he said.

Because the RPA refused to publish the figures behind its contention that there would be a benefit-cost ratio of 2:1 under a "moderate growth" scenario for Metro North, Harley was unable to examine the validity of this claim. But in a more pessimistic "no growth" scenario, he forecasts a return of just 52 cent for every €1 invested by the taxpayer.