"East Anglian pub sings such as Blaxhall and Eels' Foot were full of joining in"
With respect Brian - what happened at Blaxhall, Woodbridge, Winterton and all those other singing pubs had little to do with 'folk song' as such - they were free-for-alls where everything was sung.
Sam Larner described them, and the fishermen's concerts he attended up the East coast just like that and said "the serious singing was done at home or at sea".
The exclusively 'folk' performances were done for 'the man with the microphone'after the Beeb took an interest.
Exactly the same was claimed by the older singers in Ireland
Jim Carroll