Commencing 2020-04-17, the UK licensing authority Ofcom permitted UK licensees to append /NHS to their callsigns as part of the "Get on the air to care" campaign, a joint initiative by the Radio Society of Great Britain (RSGB) and the National Health Service (NHS), to support the emotional health and wellbeing of 75,000 licensed UK radio amateurs.
The use of /NHS for this campaign ended on 2020-07-09,
A second campaign, "Get on the air for Christmas" also permitted the use of /NHS, between 2020-12-19 and 2021-01-09.
Club Log has a software rule which would map these callsigns correctly, without the need to define a prefix or add exceptions.
However, in order to better support third-party software users of Club Log's cty.xml which may not have an equivalent software rule, the prefix NHS has been defined for England, with a start date of 2020-04-17. A set of exceptions have been added to map UK /NHS callsigns outside England to the appropriate DXCC entity.