If your video card has Composite Video, SVideo or TV out sockets and your TV has matching inputs, then you can do it with a cable from your computer to your TV.
The TV out, if it's there, has to be the right system (PAL, SECAM, NTSC, etc) to match your TV. ie, you're in UK. If, on your travels, you bought a video card from US with NTSC TV out and your TV set at home is not NTSC (which it probably isn't because UK TV doesn't use the American NTSC system), then it won't work.
You may be able to buy an RF modulator - check with your favourite electronics hobby shop.
AA