A British Metal Detectorist has reported the earliest Roman coin find reported under the the PAS. See http://www.culture24.org.uk/history/archaeology/art70536 According to the report,
West Berkshire metal detectorist Malcolm Langford brought the 207 BC silver Roman coin, along with a rare Iron Age silver coin of Eppillus, to Oxfordshire and West Berkshire Finds Liaison Officer Anni Byard for recording under the Portable Antiquities Scheme. Byard quickly indentified the coin, which is in remarkably good condition, as the earliest known Roman coin yet found in Britain.
"I was speechless," said Langford, who had already researched the Iron Age coin he had brought in. "When Anni told me the date of the Roman coin I was absolutely amazed, I couldn't believe it.”
Depicting the helmeted head of Roma and the galloping Dioscuri, the silver denarius is earlier than any of the 600 similar coins recorded by the Scheme, and may have even arrived on our shores before the Roman invasion of Britain.
"What makes the coin even more interesting is that it is in almost mint condition," said Sam Moorhead, the Scheme's National Finds Adviser for Ancient Coins. "Most Republican denarii found in Britain are very worn, as they could be in circulation for up to 300 years. This new coin suggests that some of these Republican coins were arriving in Britain before Claudius invaded with his legions in AD 43."