More than 1,000 people were caught watching TV without a licence in Harrow in 2012, according to TV Licensing.
However, the licensing body says the borough's evasion rate remains at a low level of just over five per cent, meaning almost 95 per cent of homes are properly licensed.
This compares to more than 2,600 people in Brent and more than 2,500 in Ealing. A colour TV Licence currently costs £145.50 and is required by anyone watching or recording TV programmes as they are shown on TV, whether they are using a TV set, computer, or any other equipment.
People caught watching TV without a licence could be fined up to £1,000.