The National Audit Office (NAO) have recently published ‘A short guide to the Department for Transport’ which you may find useful.

This guide is designed to provide a quick and accessible overview of the Department and focuses on what the Department does, how much it costs and recent and planned changes.

The NAO has published a suite of short guides, one for each government department, to assist House of Commons Select Committees. All of the guides can be found here: http://www.nao.org.uk/reports