Formula baby milk can have 40 times more aluminium than breast milk -- which may have an adverse affect on health.

According to scientists, traces of the metal in milk of some of the leading brands were found to be much higher than is permissible in water.

One formula made by Cow & Gate -- specifically marketed for premature babies -- had the steepest level of more than 800 micrograms per litre, reports the Daily Mail.

European law states that water can contain no more than 200 micrograms of aluminium per litre, according to the journal BMC Paediatrics.

Chris Exley, who led the study at Keele University, Staffordshire, said: 'We've known about the high aluminium content in infant formula for many years and there is evidence to show it is potentially quite dangerous.'

'It has been linked to neurological diseases and bone defects in later life and there are even links with dementia,' he said.

'Everyone has aluminium in their body but infants are especially prone to absorbing it and are not so good at getting rid of it,' he added.

Manufacturers say they do not add aluminium to their products but many formulas are often packaged in aluminium foil.

It also occurs naturally in soya plants due to the acidic soil they are grown in, so experts advise soya milk formulas should be used only on the advice of a doctor.

Exley, whose team tested 16 of the Britain's leading formula milk brands for children up to the age of one, said: 'It is concerning, especially when the product with the highest level of aluminium we found was aimed at premature babies who are likely to be the most vulnerable of all. It is really shocking.'