Are carbon monoxide detectors (CO alarms) required by law?

According to The Smoke and Carbon Monoxide Alarm (England) Regulations 2015, landlords in England are required by law to “provide a carbon monoxide detector (CO alarms) in any room used as living accommodation where solid fuel is used - after that, the landlord must make sure the alarms are in working order at the start of each new tenancy”. However, the regulations also recommend that landlords provide carbon monoxide detectors (CO alarms) in all rooms with gas appliances.