Robert Colquhoun was born in Kilmarnoch, Ayrshire. With the help of his art teacher, he was awarded a scholarship to Glasgow School of Art in 1933 and later a traveling scholarship to Paris and Italy. It was as a student that he met Robert MacBryde, who would become his life long partner. They became so inseparable at Glasgow that they were often referred to as the 'Two Roberts'.

When Colquhoun won his scholarship to travel funds were found so that MacBryde could go with him. After completing their studies, the pair moved to London in 1941, where they were introduced to the Neo-Romantic circle by Peter Watson. Outspoken, direct and charismatic, they made a huge impact on the artistic scene around them.

Their names are mentioned in countless memoirs from Soho during this time, and their Notting Hill studio in Bedford Gardens became a central meeting point for fellow artists and creatives, including Lucian Freud, John Minton and poet George Baker. During the mid-late 1940s, Colquhoun's work featured a common theme of figures in isolation, which show the influence of artists such as Pablo Picasso, Jankel Adler and Percy Wyndham Lewis.

After being evicted from their Notting Hill studio, MacBryde and Colquhoun's relationship and work faced challenges. Without the artistic community they had created for themselves, and with Colquhoun's work seeing a dip in popularity, they moved around the home of friends, staying for a time in Essex at the home of George Baker's former partner, Elizabeth Smart. Colquhoun died in 1962 at age 47, reportedly in MacBryde's arms; MacBryde died a few years later, in a road accident in 1966.

Robert Colquhoun was a central figure in the artistic world of war-time London, known for his painterly style influenced by his friend Jankel Adler. He worked alongside his life-partner Robert MacBryde and their friends John Craxton and John Minton. The duo, known as 'The Two Roberts,' gained fame under the patronage of Peter Watson and had important exhibitions in London and internationally. Colquhoun's tragically short career and the scarcity of his work on the market make his pieces highly sought after. He was active during the Post-War era, with a focus on isolated figures and a highly textural approach to painting.