First of all, get a heavy based saucepan, and heat up the water, then add the sugar. Give it a quick stir so that the sugar is evenly distributed with a wooden spoon and then leave bubbling on a medium heat until it starts to foam, this can take around 10 minutes.
Once the bubbles start to rise and fall and the liquid sugar underneath looks golden in colour, it is time to reduce the heat to low. Stir gently every 3-4 minutes, but not too much, or the sugar will crystallise too much, and you wont get the fudge like texture. Place the sugar thermometer in, and bubble to 114 degrees for the perfect fudge consistency