In an emergency situation
You should always have a plan of escape and always keep escape routes clear.
Call 999 ask for the Fire Service.
Provide your name, address and inform the operator of any other crucial information, such as, the number and location of people still inside the property and the extent of the fire.
If you have doubts on anything to do with fire safety call your local fire service authority. DO NOT contact them on the 999 number unless there is an emergency.