I've found it!

I had a problem with ants climbing on to just one of my kitchen benches. They know that sooner or later my husband is going to leave a buttery knife or a drip of olive oil (their favourites!) so they constantly send out search parties.
I don't like using poisons because I have cats and a regard for my own health.
After catching pantry moths on one of those sticky strips I had a lightbulb moment and went online and bought some insect barrier glue (in a tube rather than the pre made strips for trees) I put masking tape right round the back of the worktop (it's a freestanding unit) where it can't be seen but where the ants have to pass and applied a very thin strip of the sticky glue. Bingo. No ants! They don't even get stuck to it. they see it and maybe even touch it but clearly don't want to risk it! Today I'm going to put a strip round the bottom of the laundry room door where the big black ants get in to nick our cats food right out of the dispenser!

That is good news. I wonder though if it was the glue or the masking tape. I seem to remember reading somewhere that ants will not cross an unbroken white line, salt, chalk etc.

In UK we had an ant problem once, I did not mind them outdoors but they kept coming in under the uPVC door casement. Put down a line of salt and ya este.

We had an infestation of the moving dust ants here, a little ant trap from supermarket saw them off. They came in via the electric sockets so we could not use the white line trick.

Hmm interesting. Must try that somewhere else. I happen to have loads of talc around as I use it in my work and keep buying it when I forget tom take with me.