Should the GP feel that you would benefit from seeing a consultant or specialist, they can provide you with an open private referral letter. This referral letter cannot be used to access NHS services in the UK. Referral letters can be posted or emailed directly according to your preference.
If you have private medical insurance you will need to contact your insurer before engaging a consultant or specialist, or accessing any diagnostic or treatment services, unless you are self-funding. The referral letter is not a private medical insurance claims authorisation.