I don't know why I fell for it. I grew up with him using that tactic to nick my sweets and later my fags or spare change. I should have learned by now.
I had Whippy out, off leash because her recall is reliable. I had Devil Dog with me on his longer lead, because I don't fully trust his recall in wide open spaces. We let him off only in fenced or secure areas.
I was looking for this imaginary wild animal he had spotted, when he said "Over there, look just coming over the sand dune now with Freya (his Whippet)" and there was bloody Devil Dog 
While I had been searching for this elusive wild animal he could not identify, he'd unclipped his lead
He had a bloody good time though, he chased that whippet for miles and miles, it was an hour before he gave up but he came back 
I was so proud. He never strayed too far, when the whippet took him off too far he came back to me, at the end of the walk when we were nearing the road and I called him back, he came, when he went off tracking rabbits in bushes he came when I called him off [proud]
We're going again on Thursday. I won't bother with the long line this time. It was lovely finally being able to watch him run properly and being able to be like a real dog, if only I'd had the confidence to properly test him before now, we could have been doing this for years.