About ten minutes in as the lady is caressing her computer console, the boots on the lady behind her have shed grey paint where they have creased.
one of the Dalek props is missing the smallest ring on its eye stalk and as such has only 4 instead of 5 that are present on the other two props.
At the start of the Brigadier's phone call, both the caller and the minister can be heard at the exact same time. The minister then says "hello" twice before The Brigadier responses.
Nicholas Courtney (as the Brigadier) looks right down the camera lens a few times whilst receiving his radio alert.