From the War Cabinet Air War situation report:
Attacks on Italy.
On the 15th/16th June eight Wellingtons were despatched from aerodromes in Southern France to bomb Genoa. Heavy local thunderstorms were encountered and only one aircraft bombed the target; several hits were registered. On the following night six aircraft operated with greater success; fires were started at a factory near Milan, and the Ansaldo and Caproni works at Genoa were also hit. The aircraft and servicing units in Southern France have now returned to this country. Reports indicate that our attacks on Italy have been very successful and have created a deep impression.
See TNA CAB 66/8/42