RUTH Davidson is facing a call to use her influence over UK Tory ministers to block Scottish Government plans to merge British Transport Police with Police Scotland.

Manuel Cortes, leader of the TSSA transport union, has written to the Scottish Tory leader asking her to use her influence at Westminster to stop the power being devolved.

Blocking a piece of devolution in this way would be highly controversial. But the union says it was necessary because the change would affect the safety of rail workers and the public due to the loss of a specialist service.

The TSSA also claims it would also mean specialist BTP officers are diverted to general police calls.

Cortes said: "The battle to save this vital police service now moves to Westminster as legislation is required to enable the transfer of BTP staff and assets in Scotland to the Scottish Government. This means that the Conservative Party has the chance to thwart the proposed merger of BTP in Scotland with Police Scotland something that I know you have vigorously opposed. ?The Scottish Tories restated the party's opposition to the merger, but said Holyrood's decision must be respected.

A party spokesman said: “As the TSSA knows, the Scottish Parliament has passed this legislation thanks to a majority of SNP and Green members.We fought it every step of the way and continue to disagree with the move. But this was a decision for Holyrood, and that’s how it must remain."

The Scottish Government insisted the merger would improve safety and make railway policing more accountable. A spokesperson said: "Integration will provide a single command structure for policing in Scotland with seamless access to wider support facilities and specialist resources including Police Scotland’s counter-terrorism capabilities, providing an enhanced service provision to the rail industry and travelling public.”