Serviceman threatened with knife outside RAF base

[Stanwell]

I'm with you on that one, Heathrow Harry.
It is not at all uncommon for someone, under mental duress (for whatever reason) to make such a claim.
I do, however, have confidence that the police are seriously looking at that possibility.
As an ex-serviceman, I do NOT agree with the idea that service personnel should carry loaded firearms on civvy street.