As the nation's favourite knicker-seller, Marks & Spencer is rather a trusted hand when it comes to discerning the tastes of the nation.

As the nation's favourite knicker-seller, Marks & Spencer is rather a trusted hand when it comes to discerning the tastes of the nation.

Some have called it ‘S&M’, but partnership with Ann Summers is less a scandal than another step in a century of evolving underwear trends, experts say