The European Union executive said it had sent a final written warning to Britain -- the last step before going to the European Court of Justice -- asking it to implement the law. "By not fully complying with this EU law, the UK is not delivering the level of protection against pollution from waste water that it signed up to and that British citizens deserve," Environment Commissioner Stavros Dimas said in a statement.
The law requires that waste water from areas with populations of more than 15,000 be subject to secondary-level or biological testing before discharge.
Treatment plants should also have been up and running by December 2000, which was not done for 14 areas in the UK, 10 of them in Northern Ireland, the Commission said.
"The situation in Northern Ireland risks being exacerbated by a decision to allow substantial new development to go ahead in some areas where no appropriate waste water treatment is in place," the Commission said.
"This appears to be happening despite the authorities' own assessment that the developments pose a medium to high risk of having negative environmental impacts," it said.