Technology which allows the police to gather data from some mobile phones or tablets without using a password will be rolled out from Monday.

Police Scotland has spent more than £500,000 buying 41 desktop-sized machines which override encryption on devices.

The move has already been delayed amid concerns the technology may be unlawful.

The force insisted the devices would significantly speed up investigations.

Phones now form a major part of criminal investigations and forensic experts in Scotland examine about 15,000 a year.

The police devices – known as “cyber kiosks” – will plug into phones or tablets and trained operators will then look for information relevant to an investigation.

The only information held on devices, such as social media messages or call logs, can be accessed by Police Scotland and the force says all logs of the data captured are deleted after an examination.

Deputy Chief Constable Malcolm Graham said: “Increases in the involvement of digital devices in investigations mean that demand on digital forensic examinations is higher than ever.

“Current limitations, however, mean the devices of victims, witnesses and suspects can be taken for months at a time, even if it later transpires that there is no worthwhile evidence on them.

“By quickly identifying devices which do and do not contain evidence, we can minimise the intrusion on people’s lives and provide a better service to the public.”