Plans to merge the British Transport Police (BTP) north of the border with Police Scotland have taken a step forward with the publication of a new Bill at Holyrood.

At the same time as the legislation was published, ministers pledged that employees' jobs, pay and pensions will all be protected under a "triple lock guarantee" during the process of integration.

The Scottish Government has submitted legislation that gives power over railway policing to the force and the Scottish Police Authority (SPA) watchdog.

The Railway Police (Scotland) Bill also requires the SPA and the Chief Constable to have regular contact with train operators on rail policing and to listen to passengers and others about this.

Justice Secretary Michael Matheson said: "British Transport Police plays a valuable role in keeping Scotland's railways safe and we will ensure railway policing has a strong future and is fully accountable to the people of Scotland.

"Safety will always be our top priority and rail passengers and staff will continue to receive the high standards of security on our rail network that they are used to, throughout the period of integration and beyond."

Ministers have "listened closely to the issues raised by the rail industry, policing services and unions", Mr Matheson said, and in response "have offered a triple-lock guarantee that secures jobs, pay and pension conditions through the course of integration".

He continued: "We have been assured by Police Scotland that the specialist knowledge, skills and experience of BTP officers and staff will be protected and maintained within Scotland's wider policing service.

"As part of Police Scotland, railway policing will benefit from their local support, specialist resources and expertise.

"Cross-border policing will continue to be seamless in both directions.

"Police Scotland has excellent relationships with their counterparts and we are working with the UK Government to ensure police have appropriate powers for the entire duration of cross-border journeys."

Bernard Higgins, Assistant Chief Constable of Police Scotland, said: "We are committed to working with Scottish Government, BTP, staff associations, both police authorities and other stakeholders to ensure that should the Bill be passed that the integration of BTP (Scotland division) with Police Scotland is seamless.

"The priority for Police Scotland is to ensure all of our communities, including people who work and use the rail network, are kept safe."

Labour justice spokeswoman Claire Baker said the proposals in the Bill meant "Scotland risks losing expertise whilst eroding the cross-border nature of transport policing".

She said: "Officers, staff and unions all have serious concerns about the Government's plans, these must be taken seriously.

"The SNP should respect the independence of the British Transport Police and stop their attempts to railroad this Bill through Parliament.

"Police Scotland already faces a £27 million back hole at the heart of their revenue budget.

"We should not be putting the transport police and local policing under further risk by continued police centralisation."

Scottish Conservative justice spokesman Douglas Ross said: "The SNP's plans for the BTP don't have the support of those operating in the force just now and need to be reconsidered.

"It would have been a step in the right direction for the British Transport Police to work in conjunction with the Scottish Parliament and continue the progress that has been made over the last few years.

"Instead, the SNP has shown a niggling persistence to pass transport policing onto Police Scotland - an organisation already loaded with problems from top to bottom.

"These plans to change BTP will leave people thinking that the SNP is determined to cut ties with anything that happens to include the name Britain."