Does this not mean that GCHQ are the greatest child pornographers on the planet, by their own standards? They've successfully prosecuted and imprisoned private

Does this not mean that GCHQ are the greatest child pornographers on the planet, by their own standards? They've successfully prosecuted and imprisoned private individuals who've ended up with child porn on their computers due to botnets etc., so if they're wilfully collecting this data, they surely have a criminal case to answer?