In order to promote interest in CW the First Class CW Operators Club has arranged with Ofcom and RSGB that the call M0RSE can be used for Morse related events from time to time. Events such as CW demonstrations, Straight Key events, QSO parties, etc. but NOT contests.
In 1991 the call was used by a number of clubs and individuals and this arrangement seems to have worked very well. So the same arrangement will also apply now and the call is available to all UK competent CW operators.