Boots 'specially formulated' face spray is just a £3.99 can of WATER

But it appears that Boots's "specially formulated" facial spray is not quite as special as it seems.

In fact, it's plain old water, from the tap at a factory in Wellington, Somerset.

And although the chemist says it treats the product to remove impurities, it is hard to get away from the spray's very ordinary make up.

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The facial spray is part of the Boots Expert Range, described as "the definitive answer to those everyday health and beauty problems we all suffer from, but keep putting off".

On the back of the 150ml can, the manufacturer says its product protects skin from "dryness".

"Sensitive skin needs extra care throughout the day which is why this gentle facial spritz is specially formulated to refresh and hydrate," it reads.

"Hypoallergenic and fragrance free, it instantly cools and freshens skin, helping to protect it from the drying effects of central heating and air conditioning."

But the consumer group Which? has urged shoppers to be cautious when buying health and beauty products.

"Customers should not get carried away by the promises made by products.

"Always check the ingredients to ensure you are getting what you think you are paying for," said a spokesman.

Boots confirmed that its spray was made from tap water from the mains.

But the chemist believes it is justified in describing the spray as "specially formulated", because it has been treated.

A spokesman said: "The ingredient contained in Boots Expert Sensitive Refreshing Facial Spritz is water. This is clearly stated on the packaging as 'aqua'.

"This is the case with most facial spritzes, as the benefit is derived from applying a fine mist of water and allowing it to evaporate quickly to refresh and invigorate the skin.

"While the product is water, the process it goes through is intense and includes removing impurities and bacteria.

"The cost of the product is a combination of purifying the water and the technology needed to deliver it."

The firm's toiletries scientific adviser, Crian Wilson, said: "The water goes through a purification process and an additional process to make sure it is always in a sterile condition.

"That is one of the reasons it comes in an aerosol to ensure it remains air tight."

The pack design, which creates a cool fine mist, is what makes the product effective and ensures its popularity with customers, he added.

"I think the product is brilliant. We have deliberately not included extracts and preservatives.

"This was a conscious decision because they might get into the eyes or cause an adverse reaction."

Aqua, the Latin for water, is commonly used in the beauty industry to describe what is a staple ingredient of most potions and lotions.

Boots said there was no intention to mislead consumers by describing the ingredients as aqua rather than water.

Mr Wilson said: "The European Cosmetics Directive requires that we use the Latin name to describe the ingredients. That is the law and we are abiding by it."

The spritz spray has been on sale in Boots stores across the country since January, selling thousands of packs.

However, it is not the first time that plain tap water has been treated and dressed up as something rather more special.

Three years ago, Coca-Cola ran into trouble after selling treated water from South-East London as a designer drink called Dasani.

The company subsequently axed the drink after the discovery that supplies had become tainted with a chemical that had been linked to cancer.