Trolleys, plastic bags, old shoes and the odd bicycle are common finds during river clean-up projects - but not guns and knives.

The unexpected discovery of a bag containing two pistols and a knife was made by volunteers and members of Richmond’s Environment Trust last Saturday on Twickenham Riverside.

The clean-up crew immediately delivered the ominous find to Twickenham police station, where the weapons were sent off for forensic testing.

A police spokesman said the guns looked like “really old” pre war models. He explained that they had been sent to experts “to make them safe and then have them examined” and stressed there were no cases in the area in which the weapons had been used.

After the excitement the eco-group continued to clear the riverbed of rubbish and to explore the ecology and archaeology that lie beneath the surface of the Thames.

The event was made possible by the Draw-Off, when the Port of London carries out maintenance on the Lock at Richmond, and the river reverts to its normal levels.

The trust’s ecologist, Joe Pecorelli, said: “We are delighted to have found a healthy diversity of aquatic animals including the larvae of the mayfly, a creature which will only inhabit pollution free waterways.”

The next Environment Trust event is at Richmond Riverside on November 21 at Bridge Boathouse at 9.30am - old clothes and wellington boots are essential.

For more information visit environmenttrust.co.uk.

• What do you think? Let us know by emailing rtt@london.newsquest.co.uk, phone the newsdesk on 020 8744 4271 or leave a comment below.