Thanks to Chris Williams for the tower identification. Sea Prince T1 formerly WP321 (?) now G-BRFC, possibly at an air show. Similar towers at Lakenheath and Mildenhall look taller and are clad in red/brown brick or tiles whereas this is the right height for Alconbury which seems to have been clad with a grey finish.
another photo of Alconbury tower from Barry Davidson
the 1939-45 wartime era watchroom?