Contractors working for Thames Water this week surveyed the Thames riverbed searching for unexploded ordnance and other debris.
A Targa 31 work boat – towing a gradiometer, side-scan sonar and sub-bottom profiler – surveyed the river bed near Hungerford Bridge as well as close to MI6 headquarters at Vauxhall Bridge.
Both areas surveyed are among the sites expected to be used by the water company during the construction of its 'super sewer' tunnel under the river.
A decade ago a World War II shell was found by a dredger near Hungerford Bridge.
For the latest local news and events direct to your inbox every Monday, you need our weekly email newsletter SE1 Direct.