I answered this question in a previous thread.
There will be a restriction that will not allow you to fly public transport flights.
The following is what the CAA say:
CPL Restricted to National Privileges (“Restricted CPL”)
UK certificate holders who fail to meet the JAR should be issued with a non-JAR compliant (NJC) certificate, which confers national and ICAO (but not JAA) privileges.
This procedure has been extended to a group of initial Class 1 applicants who do not fully meet the JAR for the following conditions:-
1 Abnormal colour perception (ie assessed CP4 on lantern testing)
2 Reduced level of hearing (but within the ICAO hearing standard for professional flying of 35, 35, 35, 50 dB at 500, 1000, 2000, 3000 Hz frequencies respectively)
Such applicants can be issued with a non-JAR compliant Class 1 medical certificate. FCL will be able to issue a ‘Restricted CPL’ to these pilots that will enable them to undertake flying instruction and aerial work (but not public transport operations). This effectively replaces the BCPL.
This change has been introduced mainly because of the potential lack of flying instructors under the JAR. A significant proportion of flying instructors have, in the past, become instructors (with a UK Class 2 certificate) after failing to obtain a Class 1 certificate. With the demise of the UK Class 2 certificate, this route to flying instruction ceased until the “restricted CPL” was developed.
The limitations on the certificate will be:-
• UK airspace*
• UK aircraft*
• No public transport*
• Day flying only (this only applies to those assessed as CP4)*
• Non-JAR Compliant**
*These restrictions will need to be added to the Class 1 medical certificate before the licence is gained at which point they will be transferred to the licence.