Ministers today promised changes to the planning system to help protect Britain's high streets.

In a major victory for the Evening Standard's Save Our Small Shops campaign, the Government is proposing an "impact test" to prevent the spread of out-of-town shopping centres.

Under the new rules, local authorities will be able to turn down new developments if they believe they will have a negative effect on town centres.

The proposal was unveiled by planning minister Iain Wright during a Commons debate on saving the traditional high street. Mr Wright told MPs the Government was looking to include the "impact test" in an amendment to planning guidance - known as PP6 (planning policy statement six) - to protect "thriving town centres".

"Small, independent retailers remain at the very heart of our vision for town centres," he told MPs. His comments came after Labour MP for Battersea Martin Linton called for changes to the planning laws to protect high streets.

He said too many streets in London were becoming indistinguishable because of the march of chain stores.

He added: "We need to make councils allow diversity as one of the reasons they can turn down a planning application otherwise they are completely powerless to watch much-loved high streets turned into rows of wine bars or exclusive fashion boutiques.

"The fundamental problem is the planning system gives too much power to the whim of the market and gives too few powers to local communities."

Mr Linton said Northcote Road in his constituency was one of a number of streets "losing its character" because local shops were being "squeezed" out by big chain stores.

"We are seeing more and more upmarket clothes shops which are in danger of squeezing out the food shops which give the street its character, this is not what local people want," he said.

Campaigners seeking to protect small shops have been alarmed by proposals to open up more competition between rival supermarkets.

The Competition Commission plans aim to offer a better choice. However, some small shop owners fear they could be driven out of business if it leads to more supermarkets setting up.