Alan Fletcher's international design reputation was reflected by his commissions from major corporations and cultural institutions around the world. He was described in his obituary in The Guardian as 'the quintessential illustrator and graphic designer, a man uniquely responsible for defining British graphic design with his witty and highly individual approach from the late 1950s onwards'.

Born in Kenya, but brought up in England from an early age, Alan Fletcher studied at the Hammersmith School of Art from 1949, and then at the Central School of Art, where he met and befriended Colin Forbes, Theo Crosby, Derek Birdsall and Ken Garland. After a year in Barcelona, he returned to London to study at the Royal College of Art from 1953 to 1956, where he met Peter Blake, Joe Tilson, Len Deighton, Denis Bailey, David Gentleman and Dick Smith.

In 1956, Fletcher took up a scholarship to study at the School of Architecture and Design at Yale University. He began his career in New York where he worked for the Container Corporation, Fortune magazine and IBM. He returned to London in 1959, having worked briefly for Saul Bass in Los Angeles and Pirelli in Milan. Back in London, he co-founded Fletcher/Forbes/Gill in 1962, with clients including Pirelli, Cunard, Penguin Books, BP and Olivetti.

He co-founded Pentagram in 1972 and created design programmes for Reuters, Lucas Industries, the Mandarin Oriental Hotel Group, the Victoria and Albert Museum, Lloyd's of London, Daimler Benz, Arthur Andersen & Co and ABB. In 1992 he left Pentagram to work alone in his own studio in Notting Hill, with clients including Domus Magazine, Dentsu, London Transport, Shell, Toyota, and  Novartis Campus. Much of his later work was as art director for the publisher Phaidon Press, which he joined in 1993.

Fletcher received gold and silver awards from the British Designers & Art Directors Association (D&AD) and the New York 'One Show'. In 1977 he shared the D&AD President's Award for outstanding contributions to design with Pentagram partner Colin Forbes. In 1982 the Society of Industrial Artists and Designers awarded him their Annual Medal for outstanding achievement in design. In 1993 he was awarded the Prince Philip Prize for the Designer of the Year.

He served as President of the Designers & Art Directors Association in 1973, and as President of the Alliance Graphique Internationale from 1982 to 1985. He was a Royal Designer for Industry, a Fellow of the Chartered Society of Designers, Senior Fellow of the Royal College of Art, Senior Fellow of University of the Arts, London and was awarded an Honorary Doctorate from Kingston University. In 1994 he was inducted to the 'Hall of Fame' of the American Art Directors club.

Fletcher wrote and designed The Art of Looking Sideways (2001) and Beware Wet Paint (1996), both published by Phaidon Press. He co-authored Identity Kits - a pictorial survey of visual signs, Studio Vista (1971); Graphic design: visual comparisons, Studio Vista (1963); A Sign Systems Manual, Studio Vista; together with four publications on the work of Pentagram: Pentagram - the work of five designers and Living by Design, Lund Humphries; Ideas on Design, Faber & Faber; The Compendium, Phaidon (1989); and The Art of Looking Sideways, Phaidon (2001). Fletcher's last book, Picturing and Poeting, was published posthumously in 2006.

England & Co's first gallery opened in late 1987 in Needham Road, Notting Hill, directly opposite Pentagram's London studios, and on several occasions the gallery's exhibitions were extended across the road into the Pentagram Gallery when Alan Fletcher and other Pentagram partners thought it appropriate to their own programme. Alan Fletcher was a greatly valued friend and supporter of England & Co, and when the gallery moved to their current, larger space on nearby Westbourne Grove, he had a one-man exhibition there at the end of 2002: Thoughts on a Wall: Visual observations by Alan Fletcher, which included many of his collages, drawings, paintings and prints, including the series of works he had made in response to being in New York when the 9/11 attacks took place. An exhibition of Alan Fletcher's life's work was held at the Design Museum in London (2006-07), touring to the Ginza Graphic Gallery, Tokyo (2008), Pitshanger Manor Gallery (2008-09).