The pendant and bracelet, branded with the name Fashion Angels, were imported from China, increasing the fears among international toy retailers about the safety of Chinese products.
The Sunday Times exposed the fault when it found that a bracelet sold in Hamleys' Regent Street shop contained more than 93% lead and a pendant contained 27% lead, while the recommended safety limit is 0.06% and the UK limit 0.1%.
A Hamleys spokesperson said that immediate action had been taken to remove the "dangerous products" as soon as they became aware of the problem, and that Hamleys was reviewing its quality assurance process.
High levels of lead can cause brain damage and even prove fatal.
Nick Mather, Hamleys' chief executive, has warned that British retailers could face a shortage of popular toys in the run up to Christmas following the series of safety scares over Chinese imports.
Last week, toy maker Mattel recalled more than 18m toys worldwide and 2m in the UK, including a toy from the Pixar film 'Cars', 44 Polly Pocket toys and 11 Doggie Day Care toys.
This followed the recall earlier this month of some Fisher-Price toys, including some based on 'Dora the Explorer', because of a lead-contaminated paint supplied by a third party to one of Mattel's contractors in China.