Investigations have revealed that ammonium nitrate has been stored in excess of legal limits at Chatham Docks with no one in authority knowing.

Normally used as a fertiliser by farmers, it can also be used to make explosives - something which terrorists have done in recent years.

The information is revealed in a report to this Wednesday's meeting of Medway Council's regeneration scrutiny committee.

The maximum that can be stored without planning approval under current legislation is 1,000 tonnes.

The formal report to councillors follows the council's refusal of hazardous chemical consent to the company, Arcelor Mittal, for permission to store 2,500 tonnes of ammonium nitrate on the grounds that it posed an "unacceptable safety risk."

Angry residents protested when they discovered the chemicals were being stored in the docks a few hundred yards from their homes.

However, the company does not need council consent to store up to 1,000 tonnes there.

But suspicious council staff demanded to know whether there was any truth in rumours that higher levels had been stored illegally.

They served a legal notice on the owner of the site seeking the information.

A report to the committee says it was admitted that the potentially explosive mix had exceeded permitted levels, but was now within the legal levels.

Because there was no longer a breach of the regulations, officers had decided not to take any further action, although it was a criminal offence.

Since then the council has called on the government to change the regulations so that councils can veto chemical storage. No answer has yet been received.

The council began investigations after two ships had delivered loads of the nitrate in September, 2006, and January, 2008.

The legal paperwork was satisfactory, but both the Health and Safety Executive and the Environment Agency had objected to a larger store being allowed.

The report reveals that the chemical was to be stored in bags of 500kg and 600kg until it could be shipped onwards.

No further action is expected to be taken by councillors.