Marc Bolland, who joined M&S from supermarket chain Morrisons six months ago, said this would involve increasing the M&S brand in clothing, scaling back the number of non-M&S food lines from 400 to 100 and revamping the website.
Unveiling his three-year plan, Mr Bolland, 51, said the company would invest up to £900 million (€1,044m) on improving the business, up from an earmarked £550m. This will include an £600m investment in Britain.
The Dutchman’s strategic review came as M&S, which employs 75,000 staff in nearly 1,000 British and international stores, reported a 17% rise in half-year profits to £348.6 million for the 26 weeks to October 2.
Mr Bolland arrived in May with a formidable reputation, having turned Morrisons into a stronger competitor to Tesco, Sainsbury’s and Asda, with growth that bettered its bigger rivals.
He said the company’s first priority for the 2010 to 2013 plan would be the core British business.
In clothing, as well as boosting the chain’s own brand, Mr Bolland will look to invest in its sub-brands – such as womenswear ranges Per Una and Indigo Collection – through improved marketing and clearer positioning in stores.
Two years ago, M&S broke with 85 years of tradition by selling some of Britain’s best-loved food brands – Heinz Baked Beans, PG Tips and Kellogg’s Cornflakes – alongside its own label foods.
But Mr Bolland said branded foods will only play a role where M&S cannot develop its own, better alternative.
He said £150 million will go into the group’s online business, with a goal to double revenue by 2013 to 14.
The chief executive said the company would end its website collaboration with Amazon&.