Ben established the Festival in 2003 with Co-Funder, Sir John Sorrell. The Festival celebrates and promotes London as the design capital of the world and has inspired similar events in many international cities. It is an annual event involving 400 partner organisations and attracts almost 1 million individual visits. 

As well as managing the Festival, Ben initiates, commissions and curates projects for the event including an annual residency in the V&A Museum. In 2016 he added a new activity –  London Design Biennale – where countries, cities and territories present design installations to a theme taking over the entirety of Somerset House for three weeks. He is the Executive Director of the Biennale.

He has been a Governor of the University of the Arts London, a Board Member of the Roundhouse, and a Trustee of Artangel. Since 2017 Ben has been Chairman of the Mayor’s Cultural Leaders Board - a statutory advisory group to the London Mayor. In 2010 he was awarded an honorary degree from the Royal College of Art and graduated there in 1989. In the 2019 Queen's Birthday Honours Evans was appointed Commander of the Order of the British Empire (CBE), for services to the creative industries.