Katharine E. Hamnett CBE (born 16 August 1947, in Gravesend, Kent) is an English fashion designer best known for her political t-shirts and her ethical business philosophy. She graduated from the Central Saint Martins College of Art and Design.
Hamnett founded the Katharine E. Hamnett clothier in 1979.
In the early to mid-1980s Hamnett's oversized t-shirts with large block letter slogans, launched in 1983, were adopted by pop bands including Wham!, with her "CHOOSE LIFE" slogan prominently displayed in the music video for "Wake Me Up Before You Go Go" and somewhat less prominently in Queen's video for Hammer To Fall (worn by Roger Taylor). Taylor also wore a "WORLDWIDE NUCLEAR BAN NOW" shirt during Queen's historical appearance at the first edition of Rock in Rio festival in Rio de Janeiro, Brazil.
In 1984, ZTT's Paul Morley designed a series of "FRANKIE SAY..." T-shirts to promote the record label's chart act Frankie Goes to Hollywood (FGTH). Morley has stated that these designs were consciously based on Hamnett's slogan T-shirts: "What persuaded me was reading Katharine Hamnett saying she wanted the T-shirts ripped off, which reminded me of Mark P, saying he wanted Sniffin' Glue to be ripped off. And I mean, I did a fanzine, so when I read that I thought, great, fanzine T-shirts!" The official FGTH designs were particularly successful, and spawned many imitations of their own.
At one point, Hamnett met with then-Prime Minister Margaret Thatcher wearing her own t-shirt with the slogan "58% DON'T WANT PERSHING", a reference to polls showing public opposition in the United Kingdom against the basing of Pershing missiles in the country. In 2003, at a London fashion show, Hamnett's catwalk models wore shirts with "STOP WAR, BLAIR OUT", a reference to the looming invasion of Iraq.
More recently, models such as Naomi Campbell have appeared in Hamnett shirts bearing the slogans "USE A CONDOM" and "PEACE".
Hamnett has since expressed scepticism that t-shirt slogans accomplish anything concrete. While she now suspects that for some, the slogans are a substitute for action, a sceptic might wonder if, having served her for so many years, they are a marketing device. The "CHOOSE LIFE" slogan in the context of the day was directed at drug abuse and suicide. Because it is found in the bible ("Now choose life, so that you and your children may live" - Deuteronomy 30:19) it has been used by the pro-life movement to encourage a choice against abortion, even appearing on license plates in 27 states. Hamnett first ever British Fashion Awards, and in 1996, was voted Britain's favourite designer by readers of Cosmopolitan. The company's London shops have been designed by Norman Foster and Nigel Coates.
Beginning in 1989, with research showing pesticide poisoning in cotton-growing regions, and sweatshop labour a major part of the textiles industry, Hamnett began lobbying for major changes in the way the industry operated. After disappointment with the results, Hamnett terminated most of her licensing arrangements, and in 2005 relaunched her line under stricter ethical guidelines, including manufacturing and agricultural practices.
In 2008, Hamnett said that fashion designers participating in the London Fashion Week were racist due to what she views as increasing exclusion of black models, stating "The catwalks are full of white dogs, cosmetic companies don't like black models - the racist bitches. I have no idea why when it's obvious that black girls are just so genuinely much more beautiful than Caucasians, who have clearly got the short straw. Black girls have much better body shapes and it's such a shame. I just think there should be a bit more of a balance." 
Most recently, in 2013, Hamnett designed two different t-shirts for the Campaign for Nuclear Disarmament (CND-UK): EDUCATION NOT TRIDENT and NHS NOT TRIDENT. As an additional sign of her commitment to the anti-nuclear cause, Hamnett will join the 55th edition of the Easter demonstration at Aldermaston, on 1 April 2013. 
In 2008 Sarah Jessica Parker wore an over sized t-shirt of Katharine Hamnett with the slogan "Stay Alive in 85" for the Sex and the City film.
- Katharine Hamnett at the Fashion Model Directory
- Designers find inspiration from Katharine Hamnet for their 2003 collections, JCReport
- Hoskins, Barney (1984-10-13). "The Morley & Horn Show Present - How to Make a Spectacle of Yourself". NME. p. 25. Retrieved 2009-06-30.
- Sutcliffe, Kevin (1984-12-01). "The Road to the Pleasure Dome". The Face. p. 26. Retrieved 2009-06-30. "Indirectly, the band have Morley (a director and minor shareholder of ZTT) to thank for an income beyond the usual record company minimum. Noticing that Katherine Hamnett’s outsized polemical t-shirts of '83 were being knocked off in the high street by the spring of '84, he concocted a series of bold slogans for Frankie's second release: 'Frankie Say Relax', 'Frankie Say Arm The Unemployed', 'Frankie Say War, Hide Yourself'. 250,000 t-shirts bearing these words have been sold to date, plus twice as many pirate versions."
- Katharine Hamnett meets Thatcher. http://iconicphotos.wordpress.com/2010/05/10/katharine-hamnett-meets-thatcher/
- Day, Elizabeth (2008-02-17). "Why racism stalked the London catwalk". The Guardian (London). Retrieved 2010-05-07.
- The London Gazette: . 31 December 2010.
- New Katharine Hamnett anti-Trident designs. Available at: http://www.cnduk.org/cnd-media/item/1624-katharine-hamnetts-new-anti-trident-designs. Date retrieved: 28-03-13