Captain Scarlet and the Mysterons - Season 1 Episode 3 : Big Ben Strikes Again 1968

In the centre of London, the capital of England, a double police-escorted transporter, carrying a nuclear explosive device, built for civilian use, seemingly goes out of control, shaking of its' motor guards and its driver regaining conscience in a back alley. The transporter, now in the remote-controlled possession of the Mysterons, has been hidden in an under construction car park. Captains Scarlet and Blue are assigned to investigate the drivers' mysterious discovery, that the famous Big Ben clock struck 13 times, which may be a clue to finding the transporter, before it destroys the whole of Central London. However, the driver's founding's are more than unreliable due to his perplexed state of memory.