Well, there are no space considerations here! Even the smallest room can house a single bed 99% of the time, and if it can't then it might be time to give up on that room as a bedroom space.
Small beds in large rooms can look a little unusual - so if you have a large bedroom then even if you prefer to sleep in a single bed.
Around 30-35% of your bedroom should be taken up by your bed. For a single bed, this would mean a bedroom size of around 3m x 3m, so usually a smaller room.
We recommend to leave a walking space of at least 70-80cm around your bed or to the nearest wall, window or bedroom furniture. A standard corridor width in the UK is 90cm, so make sure you have enough room to move around comfortably!