Hundreds of police are on duty at the G8 summit

About 100 demonstrators gathered in Derby city centre to raise awareness of Africa's need for water.

Calle Lister from Friends of the Earth said police overreacted to what was intended as a peaceful protest.

Government ministers from around the world are meeting for an environment summit at nearby Breadsall Priory.

'Water not oil'

Dozens of protestors staged a "go-slow" bike ride through the city streets and some were arrested for ignoring orders against public protests.

A meeting later in the city's Market Square passed off peacefully.

Campaigners sent an oil barrel containing hundreds of water bottles to the G8 summit to raise awareness of drought conditions in some parts of Africa.

"People in Africa need clean water, not oil," Ms Lister said.

Derbyshire Police said the summit is the biggest operation the force has had to deal with since the miners' strike.

The force successfully requested powers from the Home Office to ensure protestors have to meet at an agreed central meeting place.