Look in the manual that came with your TV, or, if you've lost it, use the TV's remote to bring up the menu on screen, and search through the options to see if anything mentions "AV1 -> S-video".
My TV calls it SVHS instead of S-video (SVHS is a videotape format).

When I said "converter", I actually should have said "adapter". There is no signal conversion taking place. The SCART connector supports 3 different types of signal: composite, S-video and RGB.
If the TV does not accept S-video (the picture will be in black and white), then you will need an S-video to composite converter.