In 1989 MI5 assisted loyalist paramilitaries in murdering Pat Finucane, human rights lawyer. Not exactly "kidnapped", but in many ways being shot 14 times, at point blank range, in front of your children at home, is pretty bad.

https://en.wikipedia.org/wiki/Pat_Finucane

I think I get where you're coming from, but the two situations are really unlike each other. It's not exactly an apples to apples comparison.

If he said, then it wouldn't be a secret.