Gary Titley's Web site, www.garytitley.com was hacked, and pictures of him on the site were exchanged for pictures of the Zimbabwean president, Robert Mugabe.
Titley, who was elected to lead the UK's Labour Euro MPs this week, is reported to have first seen the defaced site when he logged on during a visit to a firm in his constituency.
The defaced site called the MEP "Garrison Titleman" and featured a portrait of Robert Mugabe on its homepage. It included small print claiming that the hackers "reserve the right to poke some fun". At the time of going to press the site was still available.
A spokesman for the MEP said, "Mr Titley was not amused. We are trying to sort it out with experts at the moment." He added, "We have reported it to police."