There could be more mail disruption from today (Thursday) and over the Bank Holiday weekend.
Communication Workers Union staff in the UK are continuing industrial action over pay which could affect deliveries to various parts of London.
Further action on Saturday could affect post to London, Ipswich, Leamington Spa, Middlesbrough, Bognor Regis and Newport.
Isle of Man Post is advising customers it is still forwarding mail as normal.
The action is not affecting Special Delivery next day guaranteed service from the Island.