But they also said antibacterial products - some of which have been banned in the United States, and are being phased out here - could cause harm to some consumers, especially pregnant women and those breastfeeding.

Environmental health professor at the University of San Francisco, Dr Barbara Sattler said: "People think antimicrobial hand soaps offer better protection against illness, but generally, antimicrobial soaps perform no better than plain soap and water."

Late last year, America banned 19 different antimicrobial chemicals, including triclosan and triclocarban, saying they were not effective and should not be marketed for use in over-the-counter consumer wash products.

However scientists fear they have merely been replaced with ones that are even worse.

British firms such as Unilever say they are phasing the two chemicals out of their products by the end of this year,adding they will be replaced by “a range of alternatives, including natural and nature-inspired antibacterial ingredients”.