A possession order is the final step in the eviction process. Your landlord can't get one without going through the courts, and the court will only grant one if the landlord has followed the correct procedure and proven a valid ground for possession, whether mandatory or discretionary.
There are different types of possession order. An outright possession order gives you a fixed date (usually 14 days, or up to six weeks in cases of exceptional hardship) by which you must leave. A suspended possession order sets conditions that you must meet to stay, typically paying current rent plus a monthly amount towards rent arrears. As long as you meet the conditions, the order doesn't take effect.
If you don't leave by the date specified in an outright order, your landlord can't physically remove you. They must apply for a warrant of possession, which authorises court-appointed bailiffs to carry out the eviction. Only bailiffs can lawfully enforce a possession order. Your landlord doing it themselves would be illegal eviction.
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