If CCTV cameras are good for ‘fighting terrorism’ how come they are never working when there’s a terror attack?

‘Former counter-terrorism detective David Videcette has blasted a central London council’s plans to scrap CCTV cameras at a time when the British capital faces a ‘severe’ terrorist threat.
The former Metropolitan Police detective, who worked on the 7/7 London bombings investigation, told RT’s Anastasia Churkina that CCTV cameras are useful in the event of a terrorist attack and that losing them would be “devastating for the police.”
Westminster City Council intends to scrap 75 cameras within its boundaries in order to save £2.7 million (US$3.5 million).’
Read more: If CCTV cameras are good for ‘fighting terrorism’ how come they are never working when there’s a terror attack?