A building materials company could face prosecution after nearly two dozen unexploded bombs and bullets were found on its premises.

The military material was discovered in a raid on the Shoreham site of aggregate firm Kendall Bros on Friday.

Police closed the A259 Brighton Road at 3pm for half an hour.

Staff and customers were evacuated from a nearby Halfords store.

The harbour master at Shoreham port was informed and ships were warned not to enter an exclusion zone on the River Adur.

A controlled explosion was carried out on 23 items, 14 of which were live, at the company's premises in New Wharf in Brighton Road.

The raid was a joint operation by Sussex Police, the Health and Safety Executive, Adur District Council and the MoD's explosive ordnance division.

Kendall Bros, whose headquarters is in Portsmouth, dredges banks around the coast for aggregate for the construction industry. The vacuum pipes it uses have been known to pick Second World War bombs and bullets off the seabed too.

When this happens companies are expected to call police at the earliest opportunity so the items can be made safe and disposed of.

Kendall is suspected to have stored the explosive material on its premises.

It is now under investigation by the explosives division of the Health and Safety Executive, which must decide whether to prosecute under the Manufacture or Storage of Explosives Regulation 2005. It is likely to take several weeks to make its decision.

John Rodway, public safety manager at Adur District Council, said: "This was an issue of public safety relating to unexploded ordnance recovered in dredging.

"The action taken in a combined operation involving the police, military and local authority should send a clear message that any explosive ordnance found must be reported to police at the time of discovery. It must not be stored on sites, especially in an urban environment."

Adur District Council leader Neil Parkin said: "When they find this stuff some companies just put it to one side until they think they have enough to call in the authorities. But they could be live shells which could go off at any time. I'm concerned live ordnance is being kept instead of disposed of quickly."

Kendall Bros was unavailable for comment yesterday.