How reconcile an immediate call on Scotland Yard with the guarantee of secrecy demanded by Forbes?
Well, he must put himself right with Forbes without delay--tell him straightforwardly that the bond could not hold.

Theydon was no lawyer, but he was assured that an agreement founded on positive wrong was not tenable, legally or morally.
He would be adamant with Forbes, and decline to countenance any plea in support of continued silence.

If Forbes's demand was reasonable, Scotland Yard would grant it.

If justice compelled Forbes to come out into the open, no private citizen should attempt to defeat the ends of justice.
"So that settles it," announced Theydon firmly if not cheerfully.

"I'll ring up Forbes, and get the thing over and done with.