Preheat oven to 180°C / 160°C Fan / 350°F / Gas Mark 4. Grease and line a 900g / 2lb loaf tin with parchment paper and set aside.
In a small bowl, whisk together the hot water and golden syrup until combined. In a jug mix the brown sugar, vegetable oil, apple cider vinegar and vanilla extract to combine.
Place a sieve over a large mixing bowl, sift the flour, bicarbonate of soda, baking powder, ginger, cinnamon, nutmeg and a small pinch of salt.
Add both liquid mixtures to the bowl of dry ingredients and whisk until you have a smooth batter - it will be very runny.
Transfer the batter to the loaf tin and bake for 40-45 minutes or until a cake tester comes out clean.
Once baked leave the cake to cool in the tin for 10 minutes, then carefully remove and place on a wire rack and allow to cool completely - at this point I recommend leaving the gingerbread overnight to let the flavours develop, but this is optional.
When the cake is cooled, now is the time to make the icing. Combine the icing sugar with the orange juice, adding more or less until you have the desired consistency. You don't want it too runny, but thick enough to coat the cake.
Drizzle the icing over the top of the loaf cake. Leave the icing to set before slicing. Store the cake in an airtight container or a cake plate with a cover for up to 3 days.