Campaigners from Barnes and Putney have planned a protest against proposals to build an entrance to London's new super sewer on the picturesque Barn Elms playing fields site.

Members of the Stop the Shaft (STS) campaign group will hold a peaceful protest outside the London Mayor's people's question time event, at Battersea Arts Centre on Tuesday, in an attempt to gain additional public support.

A spokesman for STS said: "We are surprised that Boris Johnson, who professes to be a protector of greenfield sites, has not supported our cause against use of this metropolitan open space.

"We seek his support to ensure that Thames Water use brownfield sites where they are technically feasible."

Residents who live near Barn Elms have been fighting to get Thames Water to change plans which propose the playing field would be a preferred location to construct an entrance shaft for the Thames tunnel drilling equipment.

If proposals were to go ahead, the resulting building works would mean 24-hour-a-day construction work, seven days a week, for three-and-a-half-years.

Representatives from the water company said last month that alternatives to Barn Elms were still being considered.

Phil Stride, Thames Water’s head of London Tideway Tunnels, said: “There is still a lot more work to be done, including further discussions with local communities, before we make any final decisions about the construction sites we need."

The campaigners' peaceful protest will start at 6.15pm outside the arts centre.