Some supermarkets have been charging drivers 6p more per litre of fuel, costing motorists nearly £1 billion last year, a government watchdog has found.

In response to these findings, the Government said it will look to introduce a new law forcing fuel retailers to make real-time pricing information available to all drivers.

But until then, you can find out the unleaded petrol and diesel prices in Carmarthen by using the PetrolPrices app.

Here’s a list of some of the places you can get the cheapest fuel in Carmarthen.

South Wales Guardian: Some supermarkets have been charging drivers 6p more per litre of fuel.Some supermarkets have been charging drivers 6p more per litre of fuel. (Image: PA)

The cheapest places for petrol in Carmarthen

According to the PetrolPrices app, these are the cheapest places to fill up with both unleaded and diesel fuel within 5 miles of Carmarthen: 

Cheapest places to fill up with unleaded petrol

​Texaco the Bridge (Towy Service Station)

​Price for unleaded: 139.9p

​​Morrisons Carmarthen

​Price for unleaded: 139.9p

Texaco Llysonnen Road (Tenby Road Service Station)

​Price for unleaded: 139.9p

Murco A484 (Derwydd Garage)

​Price for unleaded: 139.9p

Tesco Carmarthen Extra

​Price for unleaded: 140.9p

Gulf Priory Street (Tanerdy Garage)

​Price for unleaded: 140.9p

South Wales Guardian: Motorists paid nearly £1 billion more for fuel at supermarkets last year. Motorists paid nearly £1 billion more for fuel at supermarkets last year. (Image: PA)

Cheapest places to fill up with diesel

Murco A484 (Derwydd Garage)

​Price for diesel: 139.9p

​Tesco Carmarthen Extra

​Price for diesel: 140.9p

Gulf Priory Street (Tanerdy Garage)

​Price for diesel: 140.9p

​​Morrisons Carmarthen

​Price for diesel: 140.9

Gulf Peniel Road (Gwalia Garage)

​Price for diesel: 140.9p