The Courtauld Gallery in Somerset House is alive with the bold, expressive lines and brilliant colours of some of the earliest progressive abstract watercolours in the world.

Think of the pioneers of abstract art and you might hit upon Mondrian or Kandinsky. But before these famous painters were even born, Georgiana Houghton was creating extraordinary work that is now recognised to anticipate their style. And remarkably, this woman - who was so ahead of her time - refused credit for the exquisite watercolours and claimed she was merely the ‘conduit’.

That’s because Houghton was a Victorian Spiritualist medium who conducted séances to commune with the spirit world. She believed that the spirits of great Renaissance artists, religious figures and her late family members guided her hand. Her striking paintings are on show this summer for the first time in the UK since Houghton exhibited them herself over 150 years ago.

The psychedelic forms and swooping lines of her Spiritualist visions have an organic, sensual quality. They are mesmerising in their detail and deserve to be scrutinised up close, with complex layers that demonstrate her incredible technical skill.

Many of Houghton’s earlier works show the ‘spirit flower’ of her deceased relatives and in her more ambitious later paintings she details vivid religious visions. On the reverse of some, her notes are still legible and give an explanation of what the painting shows. This information is provided in the exhibition, adding context to the body of work and an insight into Houghton’s spiritual practice.

Houghton’s notes reveal that she intends the observer to interpret the abstract lines, shapes and colours of her paintings in order to translate the religious messages they contain. Her work communicates in a very precise language, designed to enable anyone who knows the code to divine the spirit’s intended meaning. However, should you choose to ignore her instructions and enjoy these beautiful works at face value, you will find them just as rewarding.

This collection showcases the work of one of the 19th century’s most underrated painters and is at the Courtauld Gallery in Somerset House until 11th September 2016.