The two men were shot by two men wearing Afghan police uniforms.
The inquest heard an intelligence report that said "insider threat" was difficult to detect. Insurgents and the Taliban used this kind of attack as a tactic and there had been no increase in this kind of threat.
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133 mobile phones and sim cards were found inside Birmingham Prison in the last year, according to new figures released by the government.
Cloud giving way to brighter and colder conditions
Patchy rain with clear southern parts through Sunday. Becoming brighter.