Additional required documents for minors (under 18):
• Notarized letter of authorization. A letter of authorization signed by both parents or legal guardians. This letter should also include the name of the adult who will be responsible for the children in United Kingdom. If the minor is traveling with only one parent, custody documents or a letter of authorization from the other non-accompanying parent is required. If the Custody papers were issued by a Court, then those papers have already been legalized..
If you’re under 18 years old when you apply, your long-term visit visa will only be valid for up to 6 months after you turn 18.
• Birth certificate. A copy of the applicant's birth certificate.
• Parents' passport copies. A copy of the information pages of both parents' signed passports.