What was this Childrens BBC TV series called?

Question

It ran for 6 episodes in 1989 on Wednesday evenings. It was about a boy who lived in Kent and who went diving in a pond one day where a chemical had been dumped.

The chemical was called D-22 and the boy swallowed some and became very ill. He was sent up to a London hospital for treatment.

I remember it being quite doom and gloom, and was filmed with a slight lack of colour which made it seem very austere.

Answer 1

I'm not sure what it was but from your explanation I can see why it only ran for 6 episodes, as you say very doom and gloom and not a very good story for a children program at all.  

Answer 2

I am not 100% but I think it was "The Hill and beyond" aint sure tho.