Someone told me that the main reason the immigrants were invited were to counter and break the unions. I get the feeling this person is being a little racist and making things up.
Immigrants were invited to fill a shortage of labour; since unions are stronger when there is a shortage of labour, and weakened by a shortage of work, it's a reasonable conclusion that immigration would weaken the unions, although it's unlikely that the Labour government of 1945-51 would have had this as a policy aim. The racism in the story is really that drawing labour from the Caribbean colonies was a last resort after insufficient European immigrants heeded the call.
Immigrants were invited to fill a shortage of labour; since unions are stronger when there is a shortage of labour, and weakened by a shortage of work, it's a reasonable conclusion that immigration would weaken the unions, although it's unlikely that the Labour government of 1945-51 would have had this as a policy aim. The racism in the story is really that drawing labour from the Caribbean colonies was a last resort after insufficient European immigrants heeded the call.