Sentinel is an ongoing project exploring the nature, status and relationship of pillboxes to the British landscape. First shown at George and Jørgen, London in 2011, Sentinel brings together work which includes, black and White photographs of the simple architectural structures, large photographic negatives made by turning the buildings into cameras and multi screen video installations.

Martin Newth has been transforming the small dark chambers into cameras. With the use of a simple lens and sheets of colour photographic paper Newth has made large colour photographic negatives. The images depict the scenes over which the pillboxes have stood sentinel for the past 65 years. The vivid red colour of the photographic negatives, which is a result of Newth's use of colour sensitive paper that is designed to be used under controlled darkroom conditions, show the landscape in great detail and have a dramatic theatricality that points to the buildings' original intended war time function.