[Townie]

Oh my... every single leaf on my blackcurrant bush has a million and one wee green/cream beasties on the underside 

There are greenfly beside them, but theyre not green, theyre black 

I have sprayed the undersides of the majority of the leaves with a fairy liquid solution, and the bush looks absolutely dreadful, it is covered in fruit, I just hope that I dont lose it all.

This is the first year this has happened 

[northfifeduckling]

might be blackfly, same species as greenfly. Spraying with soap would be my weapon of choice, too. Or catch some ladybirds and watch them munch away, their larvae are the best killers! Check for ants, they live in a symbiosis with green- and blackflies.