It depends upon what outputs the laptop offers, and which inputs the TV accepts.
If they've both got HDMI sockets then, unsurprisingly, an HDMI lead will do the trick. They're about a tenner in Tesco or Maplin, far dearer than that in many computer or hi-fi stores, or around £3 or £4 in discount stores like Family Bargains. (A 'Which?' survey found that the cheap ones are just as good as the dear ones).
If your laptop has only got a VGA output then you need a signal converter, not just a cable. They're not cheap!
http://www.maplin.co.uk/vga-to-hdmi-convertor-with-audio-support-388962
Chris