Microsoft's registration of the domain expired on 23rd October, and was immediately purchased by an un-named individual, said The Register. The purchaser contacted Microsoft to make arrangements to transfer back the domain. However, it appears that Microsoft largely ignored the purchaser until contacted directly by The Register, which asked why the hotmail.co.uk site was registered to a private individual.
Microsoft has yet to comment on the matter. However, it is understood that the company has now sprung into action and the transfer should be completed in the next few days.
This is not the first time that Microsoft has been caught out by a domain name renewal. In 1999 Microsoft forgot to renew its Passport.com domain, only to be rescued when a private individual kindly re-registered the domain in the name of Microsoft.
Renewal mistakes are far from uncommon – only last month Vivendi Universal forgot to renew its MP3.com domain, to be saved when musician Steve Cox paid the renewal fee of $35 out of his own pocket.
A common reason for such renewal mistakes is that the individual named as the contact for communications with the domain name registrar has left an organisation and their e-mail account has been closed. As a result, the registrar e-mails warning of the need for renewal are never received.
The Register's report can be found here