A 48-hour strike by workers on the Caledonian Sleeper service between Scotland and London has entered its second day.

The Rail, Maritime and Transport (RMT) union said its members are "rock solid in their defence of passenger and staff safety".

They walked out at 6.30pm on Monday, halting services. The dispute is over union claims of defects to trains which it says pose safety threats.

RMT reported it had received a "brilliant response" from the public after mounting picket lines in Inverness, Fort William, Aberdeen, Glasgow Central, Edinburgh Waverley and London Euston.

The sleeper franchise was awarded to Serco by the Scottish Government in March, taking over from First Group.

The union has highlighted the cost of the tendering process for the contract at £5,672,393.

In addition, it says the decision to separate the sleeper service away from the main ScotRail franchise has meant it no longer benefits from being able to draw on shared financial or engineering resources.

It also criticised the decision to outsource the upkeep of the sleeper service.

RMT general secretary Mick Cash said: "RMT salutes our members on the Serco Caledonian Sleeper who are rock solid in this second day of strike action in defence of passenger and staff safety.

"We have had a brilliant response from the public who understand what this dispute is all about and have decided to back their rail workers against Serco - the specialists in failure.

"The news that more than £5 million was blown on letting this contract, cash that could have been invested in maintaining the fleet, exposes the total nonsense of privatisation.

"RMT will continue to fight for safe and reliable services on the sleeper, and the union remains available for further meaningful talks."