Always lock your bike in a busy place with a high quality lock tied to something that is at least as strong as your lock i.e. lamp post or beefy fence. See also “How do I store the bike at home?
The safest option of course is to have your bike parked indoors. For many this is not possible or simply not practical. Our recommendations are
• to use a Motorcycle type chain or D-lock – essential
• to insure the bike; we can advise you on which companies offer the best cover (see below)
• to hide the tricycle under a full fabric cover, which we can supply
• to ask your local authority to provide you with a lockable bike shelter