OP, check your home insurance policy if you have it. Home insurance covers you against a wide range of public (third party) liability. There will be exceptions in the policy (e.g. not providing cover whilst driving a car, riding a golf scooter, flying model helicopters etc.) but riding a bike has always been covered in mine. I always make a point in checking. Check your policy details if you have it.
Some home insurance policies also offer or include legal expenses cover. My previous home insurer included it as standard but I had to buy it as an optional extra from my current insurer.
As an aside, competitive or organised events may be one of the exceptions so if you’re road-racing, time trialling etc. then you may need to take out additional cover.