There are no other dogs in our household so it's not a pack thing. It's a public thing.
He responds to a "tst" sound we make with our mouths.

I can say "wait" and make the "TsT" sound and he is responsive to this. When there are other dogs and food, we loose the control.

Thank you for all the advice. I will move the cats food and be more vigilant. I think really I just find it really awful and instantly feel frightened and powerless, worrying about what could potentially happen.

Just to add it only happens when I am there, not with my husband. He is slightly possessive over me. I am firm and he does respond to me (apart from when there are food and other dogs involved)

I find this really interesting. will this help his food obsession? He is happiest when doing this and eating revolting things in bushes..

First of all Labradors are the ultimate eating machine, they are merely a life support system for their stomach!

Secondly many dogs are obsessed with food, it is not a matter of hunger, and whilst this can make some things simple (eg training) it can be an issue when food overrides everything else.

You will not make food less valuable to him, but you CAN help him realise that you hold something more valuable than anything he can find.

Just a thought, if scavenging is also an issue, have you considered putting a muzzle on your dog whilst exercising him?

I have thought about a muzzle. Will look into it.
And Yes, the food does override everything else. He is so easy to train as well, so it is very frustrating. Thank you for all advice. I now realise it's a normal thing for some dogs and will do some reading.

Here is the best vid I have seen on how to introduce a dog to a muzzle, you do not just slap it on!

http://www.youtube.com/watch?v=1FABgZTFvHo

The best muzzles are basket types and the Baskerville Ultra is superb.

http://www.companyofanimals.co.uk/pr...e-ultra-muzzle

Your dog may look like Hannibal Lecter but it keeps him safe and other dogs safe.

HTH

Is he hungry? Sometimes the most obvious answer can be the right one......
Is he fed twice a day and fed a decent food? Does he have chews to exercise his urge to chew (dogs find it soothing).
Could he be missing something from his diet?