Towbars are now part of the yearly MOT test...........
http://www.vosa.gov.uk/vosacorp/repository/Towbars at the MOT test.pdf
http://www.vosa.gov.uk/vosacorp/repository/Towbars at the MOT test.pdf
WhoopsThe VOSA document referenced in the link clearly states that the test will be applied from the 27th April 2009. - This Year