Since it is not a simple process for the UK government to remove your child’s British citizenship once granted to them, the UKVI will never be rushed into making a decision. As a result, a Priority Service has never been available to applicants applying for British citizenship.
The only service available is the UKVI’s Standard Service, which means it could take up to 6 months for you to receive a decision for your child. Based on our vast experience, the typical processing time for a successful MN1 Registration application is about 3 months.