Yet in some sense, Escriva insisted, the blueprint for Opus Dei was contained in that original experience on the Feast of the Guardian Angels in 1928.

NPR: A Glimpse Inside a Catholic 'Force': Opus Dei

He also said there had been some success with the use of "guardian angels" - Nato soldiers who provide a round-the-clock armed guard for their colleagues while they are training their Afghan counterparts.

BBC: General Sir Richard Shirreff

Rifleman Luke Lawrence will act as one of those guardian angels, but insists that the threat of insider attacks is minimal.

BBC: UK troops prepare for Helmand tour