The ‘Queen of Shops’ will investigate how the government, local authorities and businesses can promote the development of more prosperous and diverse high streets, and will present the review by autumn this year.

‘With town centre vacancy rates doubling over the last two years the need to take action to save our high streets has never been starker,’ Portas warns.

As part of the review, she will examine the case for developing town centres that contribute to promoting economic growth, creating jobs and improving quality of life in local areas.

The review will also explore new business models for high streets relevant to the modern consumer.

The British Retail Consortium (BRC) says the review is a ‘positive step’ but emphasises that it must not penalise success.

Director general of the BRC, Stephen Robertson, comments, ‘The government is right to recognise the future of our high streets cannot be left to chance but it must take a positive approach that supports retailers of all types and sizes.

‘Independents are a vital part of an attractive retail mix but so are the big names.’

Portas has worked for John Lewis, Topshop and Harrods, where she was responsible for windows and display. She went onto join luxury retailer Harvey Nichols in 1989 as creative director and left in 1997.

She has fronted BBC2 series Mary Queen of Shops and Channel 4’s Mary Portas: Secret Shopper.

Cameron says he is confident that Portas’ ‘straight talking’ will help in the drive to create vibrant and diverse high streets.

See also: Saving the high street