In question was the site for the U.K.’s Home Office, a government department that roughly combines the duties handled by the U.S. Department of Homeland Security and the U.S. Citizenship and Immigration Services.
A link from the Home Office’s website to an outside page was the source of the problem. The link should have led to information on the UK's Technical Advisory Board. Instead, it linked to the offending Japanese porn site.
According to online reports, the original destination site had become defunct. An adult website had snapped up the domain.
A spokesperson for the Home Office said that there would be an investigation into the matter. A British citizen noticed the mistake and notified the BBC.
The error comes as an embarrassment to the British government, which has taken a hard line against adult content and supported Internet monitoring. The British government spearheaded the passing of new legislation that requires all European ISPs to keep all Internet traffic data for one year.
In addition, the country has gone to great lengths to ban what it calls "violent" pornography, drawing criticism from privacy and free speech advocates.