The company pulled two toxic products, imported from China, from its shelves and launched an immediate inquiry, a spokeswoman said.

It acted after the alarm was raised by The Sunday Times, which tested a sample of children's jewellery sold in the store.

"Immediate action was obviously taken to remove these dangerous products from our shops as soon as we became aware of the problem," the spokeswoman said.

"We would never ever knowingly sell toxic jewellery to customers and take the health and safety of our customers extremely seriously. We are urgently reviewing our quality assurance process."

A £4.99 bracelet with heart shapes sold in the London shop contained more than 93% - enough to cause brain damage and in rare cases kill a child who chewed it.

The recommended international safety limit for the chemical is 0.06%. Hamleys could not confirm if it would be testing the lead content of all its products sourced from China.

Tests by the newspaper also revealed high levels of lead in two children's products sold by Monsoon Accessorize as well as market stalls in London's Camden, Piccadilly and Oxford Street and Birmingham's St Martin's market.

It reported the company as saying it conducted regular safety checks on its jewellery and had received no complaints from customers.