Armchair fans watching England's World Cup campaign or Tim Henman at this summer's Wimbledon championship on the box will be targeted by a blitz of television licence detector vans, motorbikes and 4x4s.

Oxford has the second highest number of television licence dodgers in the South East and saw almost 2,000 snared by detector vans last year alone.

Now enquiry officers are planning to be out in force during this summer's football World Cup campaign and Wimbledon tennis tournament to catch unsuspecting viewers.

During Euro 2004, the last major television tournament involving England, detector vans snared 125 Oxfordshire people who had not paid their television licence and 72 were caught while they were watching TV coverage of last year's Wimbledon.

Hundreds of thousands are expected to watch this year's summer of sport on television and TV Licensing South West is warning viewers it will be stepping up patrols.

A fleet of detection vans will be added to 4x4s and motorbikes with sophisticated detection technology.

Jessica Ray, spokesman for TV Licensing South East, said: "Our 2005 league of shame shows that we have been even more successful at catching evaders.

"Oxford has moved up the league and this is nothing to be proud of, as it is one of the worst areas for offending in the South East.

"We do understand that there are some people who genuinely struggle to pay for the licence in one lump sum.

"But there is really no excuse for breaking the law, especially when the alternative could be as simple as a few minutes on line visiting our website."

Figures released earlier this year show Oxford moved up from eighth place in 2004 to second in a list of tax evaders in the South East.

In 2005, inspectors discovered 1,899 households were watching television without a licence. TV Licensing has a database of more than 28 million addresses allowing inspectors to focus attention on properties where there is no record of a television licence.