An old colleague from Salford who met Mcall and watched hin sing it in Salford told me he wrote it in three minutes in the back of the van before the theatre play. (my mate lived in the street next to Mcall's father and he first heard his Scots father using the expression 'croft' as a wee laddie. It was often used on the streets there.

It was also originally done in the play as a 'swing' number and I think - but can't be certain it had a saxophone on it in the original.