Cambridge University has a collection of aerial photos taken at various times after the 2nd world war. They are beginning to make digital versions available on-line. The first of these have been released and contain some images of Thurrock. For example, here is a link to the aerial photo of Tilbury Fort, taken in 1964 and shown below.
The initial release covers approximately 1,500 of the 500,000 images in the collection. Low resolution images can be downloaded through the site for research or educational use. There is more information about the project here.