Oh no! Volunteer Boris makes a splash

The Mayor of London Boris Johnson fell chest-deep into a river today in what he described as "the ultimate sacrifice" to promote volunteering.

Mr Johnson was striding through ankle-deep water as he helped to clean the River Pool in Lewisham, south east London, when he fell into a deeper stretch and sank up to his chest.

Volunteers rushed to his aid as onlookers could be heard shouting "Oh no" and "Classic".

Later, in an audio recording online, Mr Johnson said: "In order to promote this (volunteering), I took the maybe ultimate sacrifice. I decided to fall in in a very spectacular way."

The photocall was organised to show the Mayor rolling up his sleeves to help remove litter and Himalayan balsam - an invasive plant species which prevents native vegetation and wildlife from thriving - from the riverbanks as part of the 25th Annual Volunteers' Week.