Here we have the undoubted daddy of the Mars confectionery range, the dependable old Mars bar. A Mars a day helps you work rest and play the old adverts for this heavyweight used to scream. But what is it that has kept this hunk of chocolate, caramel and soft nougat at the top of the Mars table for so long?

The Mars bar was first created in Slough in the 1930s as a sweeter version of a bar they had on the American market. This bar was fairly unique in the UK market at the time, as chocolate was usually purchased in a solid block. The Mars bar differed as it has a centre of soft nougat, covered in sweet caramel, and sheathed inside a generous layer of Mars creamy chocolate.

The composition of the bar has been more of less unchanged over the years, with just a little tweak here and there to keep it popular. It has traditionally had a masculine image, and has recently transformed its advertising slogan to 'Pleasure you can't measure' to try and attract the ladies to purchase this treat.

The Mars bar comes in various different sizes from fun size through to king size for the big appetite. And also a range of other products from milk drinks to ice cream.

The regular bar weight 62.5 grams and contains around 285 calories.