In recent years, a new phenomenon has been playing a bigger role in crime across the UK.
Known as county lines, it is a process by which serious criminal gangs from larger English cities like London, Birmingham and Liverpool extend their operations into smaller cities and towns.
Violent and ruthless , they send vulnerable teenagers to these places to store, sell and deliver drugs.
Disrupting these organised crime groups is a priority for police forces across the country and nearly 600 suspected members of county lines drugs gangs were arrested last week across the UK.
In Wales, over the past 18 months, police in Swansea have smashed a number of gangs from London and Liverpool which were extending their reach into the city using this method of operating, for example.
The video above shows police involved in a drugs raid as part of Operation Avalanche. This week, the operation saw five members of an organised crime group jailed for their roles in a conspiracy to supply class A drugs to south Wales.
Stephen Haggard, 42, from Vere Street in Barry , was jailed for four years and six months; Marcus Walsh, 36, from Coronation Street in Barry, was jailed for four years and three months, Rhydian Tolcher-James, 32, from Wheate Close in Rhoose, was jailed for four years and one month; Aishan Hazelwood, 26, from Archer Road in Ely, was jailed for three years and four months and; Adam Beer, 30, from Brook Street in Barry, was jailed for one year and nine months.

Earlier this month the National Crime Agency (NCA) said they were aware of more than a hundred lines networks in Wales.
In a speech, the NCA's director general Lynne Owens said: “We now know that criminals are using more than a hundred county lines to move significant amounts of crack cocaine and heroin into towns across Wales.”
The county lines routes into south Wales:

South Wales Police
County lines drug dealing and associated criminality is a significant national problem and one which is treated as a priority by South Wales Police , the police force has said.
During a 12-month period (April 2018-19), South Wales Police reported 66 county lines-related disruptions. These disruptions included 84 arrests, 41 convictions for a total of 165 years and seizures of more than 3Kg of Class A drugs.
In a statement, they said: "Under Operation Guardian – our response to organised criminal gangs who target the most vulnerable in our society – we are committed to protecting those at risk in our communities, bringing gangs to justice and making south Wales a hostile environment for those seeking to do harm.
"Drugs gangs from London, Liverpool and Birmingham are known to be operating in the south Wales area, alongside local drug dealers.
"Intelligence suggests the number of individuals linked to county lines in south Wales is in the hundreds; however that figure relates to both criminals and victims."
As well as tackling lucrative and large-scale drug supply, Operation Guardian sought to identify and safeguard vulnerable individuals exploited by organised criminals, the police force said.
A number of cuckooing victims have been safeguarded as a result of ongoing work with local communities and partner organisations, with South Wales Police being successful in securing county lines-related convictions under the Modern Slavery Act.

Dyfed-Powys Police
Between April, 2018, and March, 2019, Dyfed-Powys Police made 53 arrests linked to county lines:
- 17 arrests from Birmingham to Llanelli
- Five arrests from Liverpool to Pembrokeshire
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Seven arrests from Birmingham to Powys
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Two arrests from Cheshire to Powys
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10 arrests from Liverpool to Powys
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One arrest from Oxfordshire to Powys
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10 arrests from Wolverhampton to Powys
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One arrest from Liverpool to Powys
Police said they were aware of lines run by drugs gangs based in the West Midlands and Merseyside in Llanelli, together with lines run by a drugs gang based in London, to Milford Haven and Haverfordwest .
In April, the force launched a 'Cuckoo Watch' in Llanelli with the aim of gathering intelligence around "cuckooing", which sees members of gangs take over the homes of vulnerable people to carry out criminal activity.
Detective Chief Superintendent Shane Williams said: "Our number one priority is to protect vulnerable people, and this includes children, who can be as young as 12 years old, and the vulnerable adults who are ruthlessly exploited by urban gangs to do their dirty work.
"Ultimately our aim is to make the Dyfed-Powys area a hostile environment for organised crime groups, preventing all forms of harm associated with these gangs.”

Gwent Police
Between April, 2018, and to the beginning of May, 2019, Gwent Police made the following arrests for drugs offences involving people who live outside of the Gwent Police area. The force wasn't able to confirm they were specifically involved in County Lines:
- Nine arrested in Newport from the Croydon area
- Two arrested in Newport from the Birmingham area
- One arrested in Newport from the Bristol area
- One arrested in Newport from the Bath area
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One arrested in Newport from the Merseyside area

North Wales Police
Between April 1, 2018, and March 31, 2019, North Wales Police made the following County Lines related arrests, and all are in relation to possession with intent to supply:
- Two arrested in Holywell – one from Merseyside, one from Skelmersdale
- Five arrested in Wrexham – three from London, one from Merseyside and one from Skelmersdale
- One arrested in Rhyl – from Manchester
- Three arrested in Mold – two from Merseyside, one from Leeds
- Seven arrested in Connah’s Quay – all from Merseyside
- Two arrested in Bangor – one from Merseyside, one from Warrington
- Two arrested in Llandudno – both from Merseyside
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One arrested in Colwyn bay – from Merseyside