Plans to block prisoners from using smuggled mobile phones will be outlined by the justice secretary on Tuesday.

Michael Matheson will appear before Holyrood's justice committee to set out the Scottish Government's new measures to stop inmates using the devices.

The country's estimated 7400 prisoners are already banned from having mobile phones but many devices are smuggled into prisons.

Some phones are even built inside prisons from smuggled in component parts.

The phones are often used to organise illegal activities such as drug dealing.

Matheson hopes new regulations will largely bring to an end to the practice.

Under the plans, networks will be banned from active phones inside the prison, leaving prisoners unable to use the devices.

Speaking ahead of his committee appearance, Matheson said: "The unauthorised use of mobile phones in prisons potentially presents a serious threat to both the security of prisons and the wider public.

"The Scottish Government has already made changes to the law to create offences for the possession and introduction of mobile phones or their component parts to prisons and to allow interference with networks within two prisons to disrupt phone use."

He added: "These regulations will further support our commitment to reducing the harm caused by illegal activity within our prisons.

"The irresponsible and illegal use of phones also causes offence to victims of crime and we are taking steps to reduce their use."