By JAYA NARAIN

Last updated at 13:46 11 February 2008

You may have thought cola wars had fizzled out - with every possible variety having now been invented.

However, Pepsi is reopening hostilities by launching a new "healthy" option.

Pepsi Raw is said to be made from natural ingredients and contains no artificial preservatives, colours, flavourings or sweeteners.

Traditional Pepsi contains fructose corn syrup, sugar, artificial colourings, phosphoric acid, caffeine, citric acid and natural flavours.

In comparison, Pepsi Raw has only natural ingredients including apple extract, plain caramel colouring, coffee leaf, tantaric acid from grapes, gum arabic from acacia trees, cane sugar and sparkling water. It is paler in colour and less fizzy than other cola brands.

By replacing corn syrup with cane sugar, Pepsi claims it has managed to reduce the calorie content of a 300ml bottle, from around 126 calories per serving to around 117 calories.

Cutting the amount of sugar in the drink could also help prevent damage to teeth.

To begin with, Pepsi Raw will only be available in selected bars and clubs in seven cities - London, Manchester, Glasgow, Brighton, Birmingham, Leeds and Liverpool, although a wider roll-out is expected later in the year.

Bruno Gruwez, Pepsi's marketing director, said: "We are really proud that the UK is leading the way with the launch of Pepsi Raw, which is the most significant innovation from Pepsi UK in the last 15 years."

The company hopes the new drink will help it catch up with Coca-Cola, which outsells all its rivals in the UK soft drinks market.

Coca-Cola held on to its position as the UK's most valuable grocery brand in 2007, despite growing pressure on shoppers to eat and drink more healthily.

Both Pepsi and Coca-Cola have numerous rival products, including several low-calorie drinks and cherry, vanilla, lime and lemon flavoured colas. Until 1903 a serving of cola contained 60mg of cocaine and to this day drinks manufacturers use extract of coca leaves - from which the drug is derived - to give cola its distinct flavour.

The UK cola market is worth £6billion a year and is dominated by the two companies that have been rivals for more than 100 years.