Busy Bees has apologised to clients after some of its customers' confidential data was left exposed to other users during an upgrade to its website.

The childcare voucher provider said the data was exposed to other users overnight on 11 February but affected parts of the site were taken down the following morning. A spokesperson said a security bug was introduced to the website during this time and the data on the members' site was only available only to registered users, and not the whole worldwide web.†

After running a series of checks on the website, Busy Bees said it is confident that sensitive information was not leaked to other users. Its spokesperson said: "We are really sorry. This has never happened before. We take these kinds of things very seriously."

Busy Bees is in the process of moving its voucher scheme onto a new website using more secure technology. It is also contacting existing customers to explain what happened.