Harness for dogs that can wriggle out?

[ShoeEatingMonster]

I'm looking after mother in laws dog for the weekend while she's away. The dog is badly trained and I think lead aggressive. He's never been taught to walk on a lead and pulls like a tank! After a particularly bad walk last night I put our dogs harness on him and he was so much better. However he soon learnt to pull backwards so it would slip off his head
I've temporarily managed so sort it by threading his lead through his collar but was wondering if there's a better style of harness that he wouldn't be able to get out of? MIL has never had him in a harness because she thinks he'll be able to pull more so I'd like a solution to give her so she sticks with it and actually attempts to train the bloody dog.

You need a Perfect Fit
You will need to actually get a tape measure to check the size, but for a wriggler it is well worth the effort.

You need something with an extra strap that sits around the dog's waist behind the ribcage. As long as the dog isn't massively fat and has no tuck whatsoever then it makes it impossible for the harness to slip off over their head. It's the only thing that will definitely stop a really determined escape artist!!

The Ruffwear Webmaster is popular (though expensive) but I really rate the Indi-Dog Houdini Ultra. I've used both and prefer the latter as it's less bulky and made to measure so easier to get a good fit. They both completely thwarted my own Houdini where nothing else has worked.

Thanks guys I'll take a look