Young offenders from the southeast of England are bringing a gang culture and so-called "county lines" drug deals to Wales, a Welsh MP has claimed.

Liz Saville Roberts said three-quarters of young offenders at Bridgend's Parc Prison were from England.

The Welsh Affairs committee of MPs visited the jail as part of an investigation into prisons in Wales.

The Prisons Service denied any policy of moving young offenders away from home to break their links with gangs.

County lines is the name given to drug dealing networks connecting urban and rural areas across the UK through dedicated phone lines.

Ms Saville Roberts said prisoners were being sent away from their homes to try to break the links with gang culture.

"But that, then, is effectively, bringing in these links and establishing county lines within communities in Wales," the Plaid Cymru MP for Dwyfor Meirionnydd said.

"We're bringing gang culture from there to here. We didn't have it here, it's not going to do us any good to have it," she added.

Image caption Drug dealers who operate a County Line from London

The director of Parc prison had said 75% of its young offenders were from England, with 45% from the south east, the Plaid Cymru MP said.

Giving evidence on behalf of the Welsh Government, Public Services Secretary Alun Davies told the committee he agreed it was "a matter of some concern".

"What I don't want to see is a facility in Wales that is being used in order simply to deal with a problem that exists elsewhere in the way which you have described," he said.

A Prisons Service spokesman said: "Proximity to home is a priority when placing young offenders in a secure establishment - combined with the length of sentence, estate capacity and risk assessment.

"Young offenders from England are sometimes placed in Welsh institutions.

"There is no policy of moving youth offenders away from home in order to break their link with gangs."