Complex sentence: Carrington is now introduced to the Doctor by Sir James Quinlan, the Minister for Technology, who explains that he is head of the newly formed Space Security Department, and that his actions were to protect the astronauts as they had been infected with contagious radiation.
Split into simpler sentences: Carrington is now introduced to the Doctor by Sir James Quinlan, the Minister for Technology, as head of the newly formed Space Security Department. Carrington says his actions were to protect the astronauts, as they have been infected with contagious radiation.