Magherafelt District Council moved quickly to remove the offending pages, which appeared when browsers clicked on www.theflightoftheearlsexperience .com

But, instead of getting a lesson on one of the most enigmatic events in Irish history, visitors to the site were offered a range of pornographic options, including adult sex toys and bondage.

Speaking to the Belfast Telegraph last night, divisional officer at Magherafelt council, Michael Browne - who is responsible for the internet - said the problem was rectified immediately.

"We didn't know anything about this until today," he said.

"It wasn't on our website. It was within the business database and as far as we were concerned it was a legitimate company.

"Once we realised what had happened we acted immediately and removed the link."

He added: "We don't need this kind of attention. No one needs it. It has certainly brought a lot of traffic to our website, but we will be reviewing all our external links after this."

Almost 400 years ago, in September, 1607 the earls of Tyrone and Tyrconnell, along with a close circle of family and associates, boarded a ship at Rathmullan on Lough Swilly, bound for Spain.

The event became known as The Flight of the Earls and is widely regarded as one of the most enigmatic events in Irish history.

Browsers who happened upon the hijacked version of the original site, however, were invited to click on a menu of 12 options, such as sex, sex toys, adult movies, swingers, sex chat and bondage.

There were also website addresses and links to a number of fellow sex sites, including 'hot date tonight', 'sex chat' and 'Find a Sex Partner on AdultFriendFinder'.

Mr Browne said that, for several years, a number of listings have appeared on the council's business database - including the Flight of the Earls Experience.

"The Flight of the Earls was based in Draperstown until five years ago," Mr Browne said.

"It was set up to promote the planatarium and the Flight of the Earls in Ulster - and that's what that site was about then. That site has obviously lapsed and some other company has re-registered that site and is now selling sex toys."

He added: "This has nothing to do with firewalls. That website did exist and we put it up in good faith."

BBC personality Gerry Anderson mischievously gave out the link address to listeners of his morning Radio Ulster show, warning them that it wouldn't be a history site they were clicking on to.