A roll film negative. On board the submarine Sealion (1959) towards the end of a long refit at Portsmouth. The photographer is in the motor room between 92 and 103 stations on the main flat looking aft and to port from the walkway at 97 station. The auxiliary propulsion control panel manufactured by The English Electric Co Ltd is on the right. Notices reading 'Do not start' and 'Do not make' are hanging on this unit. On the left above cupboard unit L50 are an automatic frequency regulator Mark 51FR and an automatic voltage regulator Mark 51VR, both manufactured by Marconi Instruments Ltd.