About �190m will go on essential improvements in 2007/08

They have tabled a Commons motion arguing it is unfair bills are going up when SWW customers already pay the highest charges in the country.

Seven MPs have signed the motion tabled by Labour MP for Plymouth Sutton Linda Gilroy including Liberal Democrat and Conservative politicians.

SWW said the rises were approved by the regulator Ofwat.

Charging 'fairness'

The motion says that average bills for customers with meters will be �378 and those without meters will face average bills of �680.

It states customers in the South West have the highest bills in the country because although they make up just 3% of Britain's population, they have to pay for cleaning 30% of the nation's coastline.

The MPs who signed the motion include: Alison Seabeck (Labour Plymouth Devonport), Gary Streeter (Conservative South West Devon), Colin Breed (Lib-Dem South East Cornwall), David Laws (Lib-Dem Yeovil), Dan Rogerson (Lib Dem North Cornwall) and Andrew George (Lib Dem St Ives).

They are urging the government to introduce a fairer system of charging and more effective help for those on low incomes.

SWW said the company always tried to minimise what it asked its customers for and people who had difficulty paying their bills could seek help.