In the UK an IFR 'Visual' approach is much different from a VFR approach:
Visual Approach
To expedite traffic at any time, IFR flights may be authorised to execute visual approaches if the pilot reports that he can maintain visual reference to the surface and:
a) the reported cloud ceiling is not below the initial approach level; or
b) the pilot reports at any time after commencing the approach procedure that the visibility will permit a visual approach and landing, and a reasonable assurance exists that this can be accomplished.
Standard separation shall be effected between such aircraft and other IFR and/or Special VFR aircraft.
Controllers shall exercise caution in initiating a visual approach when there is reason to believe that the flight crew concerned is not familiar with the aerodrome and its surrounding terrain.
Controllers should be aware that they should not clear an aircraft for a visual approach when the RVR is less than 800m. If a pilot requests a visual approach when the RVR is less than 800m, controllers should inform the pilot that this type of approach is unavailable and request the pilot’s intentions.