In 1970, Norman Foster was awarded his first major contract to design of the headquarters of Willis Faber & Dumas, the insurance firm  now known as Willis Towers Watson.

The brief was a building wrapped by a continuous glass wall and Foster consulted Francis as a glass consultant. The result was a glass wall suspended from the roof. The building was completed in 1975, became the youngest building in Britain to be given Grade I listed building status in 1991, and is still regarded as a pioneering achievement in modern commercial architecture today.