No claims bonus (ncb) is also known as no claims discount (ncd). For every year of driving without making an insurance claim, you are awarded one years no claims bonus. Say for example you have been driving for four years with your own insurance policy and haven't made a single claim, then you will have four years no claims bonus.
By acquiring NCB you are proving that you are a safe and low risk driver. The more NCB you have the cheaper your insurance quote will be. Some insurance companies class 9 years NCB as the maximum as anything over is almost irrelevant.
Protected no claims is only available to drivers with a minimum of 4 years no claims bonus (ncb). If protected no claims is taken out, in the event of a claim the drivers ncb will remain in tact. Most insurers allow 1 or 2 claims per year although this is worth checking with the individual insurance company. It is worth noting that although your ncb will not be effected, your renewal premium may still increase as you would have made a claim.
Most insurers have some type of scheme whereby you will lose a certain amount of your ncb, although not all of it. For example, if you have 5 years no claims and you make a claim with your insurer, you may lose 2 or 3 years no claims bonus at renewal time. If you only have 1 or 2 years ncb, then in the event of a claim you will probably lose all of it.
No. Pass plus is an extra driving course you can take after passing your driving test. Some insurance companies will take a pass plus certificate as one years no claims, although not all of them do.
The only way to gain no claims bonus is to have your own insurance policy and to not make a claim with your insurer. Being a named driver on someone elses policy will gain nothing except driving experience.
Most insurers require that your current no claims certificate must have been issued in the last two to three years. If you have 5 years no claims, and then dont drive for 3 or 4 years, when you start driving again it is likely you won't have any ncb.
Some insurers will count claim free company car driving years as no claims bonus. Often you will need to prove it via a letter from your boss that you haven't had an accident and then your insurance company will count this as no claims bonus.