By Marina Kim
Labour's Nick Ainger lost his seat in a key Tory target.
The Conservative candidate Simon Hart won by a large margin, gaining 16,649 votes (41.1%) over the Labour incumbent who received 13,226 votes (32.7%).
The result represents a 6.9% swing from Labour to the Conservatives.
The electorate is split between the English-speaking rural areas in Pembrokeshire and the Welsh-speaking urban areas in Carmarthen.
The constituency needed to be won by the Conservatives if they were to have a realistic chance of forming the government. A hung parliament remains the most likely result, however.