Buying a bikeCheck if you are eligible through your work to purchase a new bike through a cycle scheme. These schemes can offer excellent payment terms and discount the cost of a new bike.
I've had good personal experience when making claims for theft or damage to bike from collision through The Ethical Choice, which is an ethical insurer.
There are other specialist cycle insurance companies, and you can compare them on a website such as Cycle Insurance.
This type of insurance may be over the top if you don’t possess a top of the range bicycle, so you may prefer to include it on your home insurance policy, under the All Risks section. Some specialist companies require you to keep your bicycle indoors or in a locked brick shed, and secured to the floor. Home insurers are unlikely to specify this.
Third party cycle insurance
Cycling UK membership includes third party cycle insurance as well as many other benefits. Definitely worth becoming a member if you are a regular cyclist, both for leisure and commuting. They also have a legal advice helpline for members.