A Llandybie woman has been arrested following the alleged theft of a six-figure sum from a doctors' surgery in Ammanford.

Mother-of-three Dawn Beynon has been released on police bail following a suspected £200,000 fraud at the town's Margaret Street Practice.

Mrs Beynon, now living in Swansea, was the surgery's practice manager before her departure last December.

A Dyfed-Powys Police spokesman said: "Our fraud department can confirm that they are conducting a criminal investigation, having received a complaint that a substantial amount of money has been stolen from the Margaret Street doctors' surgery accounts.

"The case is in its early stages. One person has been arrested and is currently on bail pending further enquiries."

Last week, the Guardian reported how officers from the London-based NHS Counter Fraud and Security team had already begun an investigation into the missing cash, although spokesman Matthew Willis refused to give details of the operation.

"I cannot confirm anything at all at this moment in time," said Mr Willis.

"All I can say is that the NHS counter fraud service investigates all allegations of fraud within the NHS thoroughly and properly."

A spokesman for the Carmarthenshire Local Health Board said that because Mrs Beynon was a former member of staff at the practice, its officers would play no part in the investigation.

"This is an issue for the surgery itself," said Yvonne McLavy.

"As the person involved has been employed by the surgery and not the LHB, the incident would be investigated by the surgery."

A spokesman for the Margaret Street Practice refused to answer any questions about the investigation.

"I have no comment to make whatsoever," the spokesman said.

Last week, a national Welsh newspaper carried an advertisement in its jobs supplement for the vacant Practice Manager's role at the Margaret Street surgery.

The Margaret Street Practice came into being in August 1986 with the construction of a purpose-built surgery following a series of mergers between practices at Ammanford's Hall St, Llandybie and Tycroes.