My ensuite bathroom,has suddenly started to smell of petrol,I have no idea where this could be coming from,possible mitigating factors: the toilet is unused as broken,and the street is being dug up for gas works?
The room has no windows only a small extractor fan.

Hi Suzy

If the toilet is
unused as broken, then most likely the toilet trapway has dried up and is allowing sewer gasses to escape into your home. Further, any other fixtures in the bathroom that are not used at least once a week could also have PTRAPS where the water has evaporated and also allowing sewer gasses into the home.

To check to see if this is your issue simply run water in all fixtures in the bathroom on a frequent basis. Today, just pour a few gallons of water into the toilet BOWL and run water in the fixtures and see if that reduces/stops the smell over the next 24 hours (open window to let room breathe/clear or turn on the bath ventilator fan if you have one).

Let me know if that resolved the issue or not, OK?

Mark