In 2011, Portas moved from BBC to Channel 4. Her first series for the channel was Mary Portas: Secret Shopper which aired in January 2011.
In August 2011, Portas opened her own shop, called "Mary & House of Fraser" within UK department store House of Fraser's Oxford Street flagship. The store stocks her first fashion collection, called 'Mary Portas', as well as other product collaborations including a footwear collection with Clark's - "Mary & Clark's", and a hosiery collection with Charnos - "Mary & Charnos". Portas also launched a new product, 'Armery', which is a hosiery-type garment for the arms. The product is designed to "banish bingo wings".
In March 2011, Portas regularly appeared in the Channel 4 series Lily Allen: From Riches to Rags, in which she advised the pop star on her venture into fashion retail.
In August 2011, she opened her first retail shop as a concession in House of Fraser's Oxford Street branch. The shop, named Mary & House of Fraser, sells clothing and lifestyle products aimed at the 40+ female market, and was filmed for a Channel 4 documentary Mary Queen of Frocks that aired in October 2011.
She spends her money on art, wine, theatre and chocolate, and enjoys gardening. She was named as one of the top 100 Tweeters in the UK by The Independent in 2011.
In May 2011, she was appointed by the Prime Minister David Cameron and Deputy Prime Minister Nick Clegg to lead an independent review into the future of the high street. She published her report "The Portas Review" on 13 December 2011. Portas states the aim of her review to "put the heart back into the centre of our High Streets, re-imagined as destinations for socialising, culture, health, wellbeing, creativity and learning". The review goes on to detail 28 specific recommendations and on 13 December, the Prime Minister David Cameron issued a statement thanking Portas for her review and explaining that the Government would respond to her recommendations in spring 2012. Cameron said "I am delighted that Mary Portas has produced such a clear vision of how we can create vibrant and diverse town centres and breathe life back into our high streets."