The group is now searching for a replacement for a role that oversees four PA staff and reports to group director of corporate and government affairs Mary Fagan.
Fisher's exit comes as Royal Mail has been lobbying the Government to set up an employee share-ownership scheme that would give postal staff a 20 per cent stake in the company. The company hopes the proposals will secure the co-operation of workers in its restructuring, in which jobs have been cut.
Fisher was unavailable for comment but is understood to be leaving of his own accord. It is not clear whether he has another job lined up. A spokesman said: ‘Mick has decided to leave after seven years as head of government relations.
Royal Mail is sorry to see Mick go and wishes him all the best for the future.'