Read your tenancy agreement for what its says about rent arrears.
There is no law that is only about your rights on rent arrears. Your tenancy agreement says what rights you have on rent arrears, if any.
Social housing tenants
People renting from a social landlord like Brent Council or a housing association have more rights than private tenants. Social landlords have to follow a strict process called a rent arrears protocol. If your landlord does not follow the right process you can complain.
NHAS – social landlords arrears protocol fact sheet
The only rules that landlords have to follow about private rent arrears are what it says in your tenancy agreement.