Waunarlwydd dealer who bragged he sold ‘the best Valium in Swansea’ jailed for three years
Sean Brendan Doyle, 36, was arrested after Gorseinon neighbourhood officers executed a warrant at his home and seized drugs, cash and multiple mobile phones linked to street dealing. When police tracked down his Vauxhall Astra in Sketty Park, they opened the boot to find bags and boxes stuffed with tablets.
Inside were 1,535 tablets across six different Class C drugs — most of them diazepam — along with 2.1g of cocaine and four phones packed with messages about deals, discounts and bulk orders.
Dealer bragged about his ‘best in Swansea’ supply
Swansea Crown Court heard Doyle had been supplying diazepam for at least a year, selling £15 and £20 street deals and offering cut‑price rates for bigger orders. In one message he bragged he’d been selling “the best diazepam in Swansea for 15 years”. In another, sent just days before his arrest, he talked about shifting 10 boxes a week and wanting to move into bulk sales.
Doyle refused to answer questions in interview and wouldn’t give police the PINs to his phones. But officers were still able to download messages showing a steady trade in Class C drugs — and occasional Class A supply.
Long history of drug offending
The court heard Doyle has seven previous convictions for 13 offences, including supplying Class C drugs in 2009, possession with intent to supply in 2017, and further drug offences in 2021.
His barrister said Doyle had used Class C drugs from a young age following “tragic events” in his life, and claimed his drug use spiralled after the suicide of a friend in 2023. The court was told he is now drug‑free and credits his new partner for helping him turn his life around.
Judge Huw Rees said he would not “lecture” Doyle but told him he already knew that turning to drugs “only makes things worse”.
Doyle admitted possession with intent to supply crack cocaine and two counts of possession with intent to supply Class C drugs. He was jailed for three years, serving up to half in custody before release on licence.
Police: ‘He was peddling misery’
Sergeant Molly Llewellyn, South Wales Police, said Doyle had been “peddling drugs and misery onto the streets of Waunarlwydd and wider Swansea”.
“But, like so many drug dealers before him, he was found out by police,” she said. “Our neighbourhood teams are committed to listening to residents, acting on their concerns, and disrupting those involved in this unlawful activity.”
Police urged anyone worried about drug dealing in their area to report it.
Related stories from Swansea Bay News
Swansea man jailed after police find massive cannabis haul in garden shed
Officers uncovered a large cannabis grow hidden in an outbuilding during a routine search.
Dealer jailed for eight years after routine stop uncovers £150k drug haul
A simple traffic stop led police to a huge stash of cocaine, cash and drug‑dealing kit.
Police warn landlords after cannabis factory found in Swansea rental home
Officers urge vigilance after a rented property was turned into a sophisticated grow site.
Swansea drug line boss jailed after police find SIM cards hidden in waistband
A county lines organiser was caught with multiple SIM cards used to run a drug network.

