We have several colonies in and around the garden. So far the crystals that look like sugar seem to be the best deterernt they take the poison down to the nest which kills them.

Yes I have problems with ants! We had a big problem a few years back, they were in our kitchen too, I tried everything from the shops which did not work, in the end a pest controller, told me petrol is the only way to get rid of them and this did work, I had no ants for about five years until this year, I know it's a bit unconventional.
Depending on how big the nest is you might have to give it several attempts. I bought a children's syringe from the chemist and just squirted it in the spaces that they were coming out of, which was several.

Hope this helps and good luck!!

I’ve had an infestation of ants in my home early last year.

I was eating my breakfast in the lounge and felt an itch… the room was swarming with hundreds of ants . I tried the Nippon gel which had virtually no effect.

In desperation I tried the only other thing I had in my home that I thought might work… This was Acclaim 2000 a spray you use on carpets if there’s a flea problem ( I have a cat)

The effect of this on the ants was miraculous . They died almost instantly and I sprayed a little on the spot where they were getting in and I didn’t see another ant from that moment.

Later in the year I noticed ants coming in through my study window ( I have ivy growing up the outside wall.) A quick spray around the windowsill and no more ants!

The first new ant comes into contact with the spray and they do a very rapid about turn… they do not like it at all!

You can get Acclaim 2000 on the internet ( just Google ) or via your vet

Yes it is due to the rain - they don't want to be flooded out so nest nearer the surface, hence you see more at the moment.