CONTROVERSIAL pesticides linked to declines in bee populations may potentially harm the developing brains of unborn babies, European safety experts have ruled.

They have called for recommended exposure limits for the nicotine-like chemicals to be lowered while more research is carried out. Three neonicotinoid pesticides are already subject to a temporary ban throughout the European Union because of concerns about harm to bees.

The two-year moratorium takes effect from this month. While accepting the ban, the UK Government has said it rejects the science behind it.

One of the banned chemicals is one of two neonicotinoids now at the centre of a new warning relating to human health.

A statement from the European Food Safety Authority said the insecticide imidacloprid "may affect the developing human nervous system". Similar concern was expressed about another neonicotinoid called acetamiprid, which is not affected by the ban.

The move follows research on rats showing offspring exposed to imidacloprid suffered brain shrinkage, reduced activity of nerve signals controlling movement and weight loss. Another study found acetamiprid exposure led to reduced weight, survival and response to startling sounds.