Get fresh air immediately.
Open doors and windows,
turn off gas appliances and leave the house
See your doctor immediately or go to hospital – let them know that you suspect carbon monoxide poisoning. They can do a blood or breath test to check
If you think there is immediate danger, call the Gas Emergency Helpline
Get a Gas Safe registered engineer to inspect your gas appliances and flues to see if there is a dangerous problem
Don’t assume your gas appliances are safe: get a Gas Safe registered gas engineer to do a check. This is the only safe way to prevent yourself and those around you from incurring serious illness or death due to carbon monoxide exposure.