Thomas's exhibtions include The Royal Watercolour Society at Bankside Gallery, the Art on Paper Fair at the Royal College of Art, The Watercolour and Drawing Fair, London, The Royal Institute of Painters in Water Colours and The Royal Society of British Artists.

Thomas's work was also shown at The Singer and Friedlander/Sunday Times Watercolour Competition Exhibition held at the Mall Galleries which also toured to The Sculpture Hall, Manchester Town Hall.

In the last year his work has been exhibited at the Glasgow Arts Club with the Royal Scottish Watercolour Society (RSW), Fabriano Museum, Fabriano, Italy, the Wagner Art Gallery, Sydney, New South Wales and the Wollongong City Art Gallery, Australia.

Thomas undertakes many commissions, with clients including St Albans Cathedral, Knebworth House, Deloitte & Touche and the BBC. Thomas is listed in Who's Who in Art and Antiques.

Thomas' work can be found in the collections of the BBC at Broadcasting house and in many private collections in the UK and worldwide, including those of the Bishop of St. Albans and HM The Queen.

Thomas's work featured in an Exhibition at the Royal Albert Hall in April and May 2011. The exhibition "A Year in the Life of the Roya lAlbert Hall" The exhibition was a culmination of a year long partnership between the Royal Watercolour Society and the Royal Albert Hall.

From 2009 to 2012 Thomas was Treasurer of the Royal Watercolour Society.

Thomas is President of the Royal Watercolour Society.