Ask an Immigration Solicitor. Get an Answer ASAP.
Are you British from birth? If not what date did you acquire British citizenship. What are the dob of your children?
Were you born abroad?
You may be able to make an application to register your children as British but any application can only be decide on discretionary grounds.
Before you embark on an expensive application you must seek full legal advice.
I would be grateful for a 5 star rating at the top right hand corner.