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 , are n'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 , does n'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 .
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 . He was told it would be marmalade people in Devon do it in reverse .