text: It is the biggest culinary question which divides the Westcountry: when eating a scone, do you add jam or cream first? Today David Cameron waded into the long-running dispute, and quickly got into a muddle about the Devon and Cornish way of eating a cream tea. The Prime Minister made the gaffe on a campaign visit to Devon, before risking the wrath of purists by claiming 'it all tastes the same'. Scroll down for video . David Cameron, on a visit to Devon this morning, made the blunder of confusing the two methods for eating a cream tea . How do you eat your scone? How do you eat your scone? Now share your opinion . The Tory leader has spent the day campaigning in Devon, where he must win several seats if he is to stand any chance of winning a majority. But his hopes of courting support in the county were given a knock with his food faux pas as he chatted with staff and customers of Tea by the Taw on The Strand in Barnstaple, the North Devon Gazette reported. All good politicians know how to make small talk with voters, but the jam and cream debate is no trifling matter. In an attempt to woo the locals, Mr Cameron ventured: 'When you are in Devon you do the jam and the cream in a different order to Cornwall, is that right?' Sensing a gaffe was imminent, he went on: 'I'm going to get this wrong, aren't I?' His prediction was correct, as he added: 'In Devon it's... jam first and cream on top?' His comments were greeted with silence and stony faces, as the staff realised someone was going to have to put the Prime Minister right. 'Wrong way round. I knew I'd get it wrong,' Mr Cameron said. 'It all tastes the same, doesn't it?'. Wrangles over whether it should be jam first or cream, and whipped cream or clotted, have been running for generations, with references to the sweet treat dating back to the 11th century. The Devon tradition is to slather the scone with cream first, while the Cornish – who also lay claim to inventing cream teas – prepare their scones the opposite way. Two years ago, an academic devised what was claimed to be the mathematical formula for the perfect cream tea, and it used the Cornish way. Dr Eugenia Cheng, of Sheffield University, concluded that the best weight ratio is 2:1:1, which means an average scone, weighing 70g, requires 35g of jam and 35g of cream . The Tory leader has spent the day campaigning in Devon, where he must win several seats if he is to stand any chance of winning a majority . Academic Dr Eugenia Cheng, of Sheffield University, devised what was claimed to be the mathematical formula for the perfect cream tea, and it used the Cornish way. Dr Cheng set the ideal thickness of the scone, with all its elements added, at about 2.8cm, allowing a relaxed open width of the mouth when taking a bite. The equation also specifies the thickness of the cream and jam layers. Dr Cheng's formula is a victory for Cornwall, with jam spread first due to avoid it running off the edge. Another rule in the scientific method is to use clotted rather than whipped cream. This is due to the excessive volume of whipped cream needed to satisfy the weight ratio. The thickness of the layer should not exceed that of the scone.
target: Prime Minister makes culinary blunder as he tries to woo Devon voters .
  Chatting in a Barnstaple cafe, he tried to guess jam or cream first .
  Cornish use jam with cream on top, but people in Devon do it in reverse .