THE controversial merger of railway policing was shelved after Police Scotland warned of a potential pension black hole of up to £100m.

SNP Ministers wanted to integrate the British Transport Police (BTP) with the single force by spring next year, but the timetable was scrapped after a critical internal report was produced on the policy’s finances, staffing and resources.

The joint report by Police Scotland, the BTP and the transport force's Authority also claimed that the amalgamation could be subject to a judicial review.

Labour MSP Daniel Johnson said: “The SNP government has turned the BTP integration into a shambles. This leaked paper shows the myriad of problems facing the integration. The pause provides the opportunity to look again at the whole re-organisation of BTP and if the government cannot build a proper business case for the proposals it must halt the integration altogether.”

READ MORE: Theresa May "the block" to getting a deal on Brexit Bill, insists SNP leadership

After railway policing was devolved to Holyrood, MSPs last year passed Government-backed legislation to merge the BTP in Scotland with the single force.

A ‘go live’ date of April 2019 was announced and a Joint Programme Board (JPB) was set up to implement a policy opposed by opposition parties and stakeholders.

In February, against a backdrop of mounting criticism, Justice Secretary Michael Matheson ditched the spring 2019 timescale and backed a “later” integration date.

The u-turn was made on the same day a highly critical paper co-authored by the two forces and the BTP Authority was presented to a JPB meeting.

In one passage, the bodies noted that Police Scotland’s “change function” and “digital transformation team” would be “significantly diverted” if April 2019 remained in place.

The paper added: “Police Scotland are not prepared to divert resources away from the Policing 2026 Transformation Portfolio...”

It listed twelve “benefits” of moving the start date, including ensuring that a “proper basis in law” existed to integrate BTP personnel.

According to the paper, the “level and quality” of communications with BTP staff and officers had been “insufficient” and increased the risk that Police Scotland would “lose these people”.

HeraldScotland:

HeraldScotland:

Images: extract from the leaked report

The document claimed that April 2019 would be problematic in relation to agreements with train operating companies, which help fund BTP: “This creates a significant risk of judicial review for Police Scotland and the SPA.”

On finance, Police Scotland was said to have “very limited capacity” to deliver integration, while concerns about possible workforce costs were underlined:

“There is also large potential financial liability in particular the estimated £45m -£100m associated to the transfer of the relevant pension fund.”

It added: “In relation to the potential Pension Liability the team are working with Scottish Government to give indemnification and underwrite the cost although this has not been secured yet.”

The first recommendation was unequivocal: “That April 2019 for ‘go live’ is no longer achievable and that this should be communicated to Ministers, officers, staff and other stakeholders.

READ MORE: Theresa May urged to "come clean" by SNP over claims of improper referendum spending

A table at the end of the document listed ten issues on a scale of readiness, with a mark of “one” indicating significant risk and “five” meaning “ready for integration”. Seven of the categories were assessed as “two”, while the remaining matters were classed as a “three”.

A Police Scotland spokesperson said: "Planning for the integration of BTP continues and we are working closely with BTP and other partners. The priority for Police Scotland, as always, is to ensure that we continue to deliver the highest possible standards of service and that all of our communities, including people who work on and use the rail network, are kept safe."

A Scottish Government spokesperson said: “We are working with the UK Government to ensure the legislation passed by the Scottish Parliament last year is implemented safely and effectively, providing an enhanced service to both the rail industry and travelling public. We are committed to our triple lock guarantee to protect jobs, pay and pensions for BTP officers transferring to Police Scotland. We have met with the BTP Federation on a number of occasions in recent weeks and will continue to work closely with them on addressing issues raised by their members."

The BTPA declined to comment.