Joshua is an enthusiastic and experienced art historian and lecturer who thoroughly enjoys sharing his love and knowledge of art, photography and visual culture with an audience. He is an experienced lecturer in 19th and 20th century European and American art, international contemporary art, photography, design and architecture. Teaching for 20 years at Christie’s Education, the college of Christie's auction house in London, he can provide a lecture or study day with his listed talks or create bespoke talks on request, for example to coincide with a temporary exhibition, special event or anniversary.

At Christie's Education, Joshua was director of The London Art Course and many other courses in the field of modern and contemporary art, ranging from Impressionism and Surrealism to photography and modern sculpture. He has also taught on the client VIP courses for the Chairman's and President's offices at Christie's, the world's biggest art business.

Drawing on his media experience as a former BBC journalist, Joshua is also a founder and presenter of The Art Channel, an online project documenting and interpreting art exhibitions and artworks in museums and commercial galleries. The channel has now received two million views.

Joshua has direct experience of the art market while working as the Director of Hamiltons Gallery between 2018 and 2020 specialising in 20th Century photography. At Hamiltons, he exhibited and represented Don Mccullin and the estates of Richard Avedon, Irving Penn, Helmut Newton and Herb Ritts.

Elsewhere, he has lectured for Sotheby’s Institute, The University of the Arts, The University of California, Cheung Kong Business School (China's leading business university), Tate Modern and Tate Britain, The Victoria and Albert Museum Academy, The National Portrait Gallery, Somerset House, The Design Museum, Union Bank of Switzerland, Artemisia, P & O Cruises and Mr and Mrs Smith. Further to his institutional work, he has worked with numerous private clients (including many former students) in London and led groups abroad to visit Berlin, the Venice Art Biennale and the influential art festival, Documenta in Kassel, Germany. In the UK, he has led groups to visit Bristol, Cambridge, Chichester, Liverpool and Oxford. In 2026, Joshua will be leading tours abroad for Kirker Cultural Tours and ACE Cultural Tours.

On television and radio, Joshua has been a guest contributor to Channel 5’s ‘Great Paintings of the World with Andrew Marr’, BBC Radio 4’s ‘Behind The Scenes’ and BBC Radio 3’s ‘Turning Picasso.’ As a writer, Joshua has written exhibition catalogues and been published by Hamiltons Gallery, the BBC, The FT, Christie’s Magazine, Flash Art, Wanderlust, Decanter, Lonely Planet, Mr and Mrs Smith and The Nicola Erni Collection of art and photography in Switzerland.