hi thanks i must get it read. someone told me it could be a relay what would you think?

I agree - you need to know the fault code. Your breakdown service will come out to read it especially if you're in the next town and tell 'em you don't want to continue your journey until you know it's safe to do so. In fact, you should have done that when the light first stayed on! You're driving it with the light on and yet the code generated might be pointing to a looming catastrophic failure! I drive with my little yellow light on, though, because the code is for 'EGR performance' and it comes and goes. I'm waiting for a spell of dry weather so's I can get the EGR valve off - complete with it's exhaust gas cooler pipe and all the top of the engine including fuel filter to get at it!! I got myself a forty-quid fault code reader from my local car parts shop so that I can make sure that's the only code showing!