For the record, "Honour bright" is also an expression—something British (and maybe Irish) kids say (or used to say) to "swear" the are telling the truth, or to seal a promise, like the American equivalent, "Cross my heart and hope to die."

The phrase occurs several times in D. H. Lawrence's short story, "Rocking-Horse Winner," which includes a lot of dialogue between a young boy and his uncle. For example:

"Yes, I am. But it's between you and me, uncle. Honour bright?"
"Honour bright all right, son! But I must talk to Bassett."

There is an old scout song called "Scout Vespers," repeated in many places on the Web, that contains the lines, "Have I kept my hono(u)r bright? Can I guiltless sleep tonight?"