Dead Ringers

The Doctor:
Is this B&Q?

B&Q Employee:
Yes.

The Doctor:
Ah, good, this is the Doctor. Tell me, do you sell sink plungers?

B&Q Employee:
Yes.

The Doctor:
Do you sell dustbins?

B&Q Employee:
Yes.

The Doctor:
Do you sell wooden dowels?

B&Q Employee:
Yes.

The Doctor:
And when Minis drive by, do they ever have little blinking orange lights?

B&Q Employee:
Er...yes?

The Doctor:
Ah, my friend, if you have dustbins, sink plungers, wooden dowels and Minis driving by with little blinking orange lights, you are in great danger! Your shop may well be the invasion corridor for the Dalek army! You must flee at once!