you should be able to get personal accident cover and critical illness cover through any broker. Premium depends on many factors, including occupation. naturally, a watchmaker would be a lower risk than a steelpejack!
You should also look into Income Protection, which is generally superior to personal accident cover (in that it has a broader range of cover including disability & illness) and will pay an income up until 65. As the other others stated, the cost will depend on personal circumstances but their is tax relief on income protection but not on personal accident policies.