The Skovox Blitzer

When a single one of these high-tech killers invaded modern day London it was enough to put the whole of humanity in danger. The Blitzer had enough explosives in its armoury to destroy the entire planet, meaning suddenly, nobody was safe.

The Doctor suspected the Blitzer had arrived in the area after homing in on artron emissions and aware that a misjudged military attack on the invader could end in catastrophe, he opted to take care of the problem himself. ‘I give the Blitzer a tiny whiff of non-threatening alien tech,’ he told Clara, explaining his plan, ‘[and] lead it here… I've set up a circle of time mines round the school. Chronodyne generators. Bit unstable. I switch them on, Blitzer gets sucked into a time vortex, billions of years into the future. Dead easy!’

When Danny’s meddling ruined the plan the Doctor tried to reason with the Blitzer, appealing to a sense of morality that apparently didn’t exist. He revealed he was unarmed and offered to help the machine, but the reply was the ruthless battle cry: ‘Problem-solution-DESTROY!’

The Doctor gambled that the Blitzer would follow orders without question, even if its own existence was at stake. When he was able to imitate its superior officer, he persuaded it to shut down and later dumped it in deep space. The gamble had paid off! ‘Farewell, Skovox Blitzer,’ the Doctor said as he watched the murderous machine drift away, ‘Have a nice war!’