Unless they are causing you a problem I would leave them alone they do a lot of good work in the garden. If you MUST kill them then boiling water down the entrance to their nest or powder puffed at entrance. But, I repeat, unless they are causing you a problem I'd leave them be. Ants nests in pots and containers are a different thing.

Hi Guest,

Generally speaking, as MG says, ants are useful in a garden, and form an important part of the whole ecosystem, but they can become problematic in pots or if they build nests in the wrong place.

Ecocharlie sell something called "No Ants":

http://www.ecocharlie.co.uk/grow-your-own/pest-and-disease-control/nemasys-no-ants.html

which is an environmentally friendly nematode that you simply water into the pot/soil etc., and which will effectively drive the ants out of the pot and the immediate area surrounding it.

I agree, I leave them alone in my garden and perhaps that is why they dont come near me or the house? It was their presence on my new ornamental cherry tree that alerted me to the fact that I had an infestation of black fly.

Useful little beings...

Fascinating creatures too....with up to 20,000 species, which make up anything up to 25% of the planets biomass, they are arguably the most successful animals ever to have evolved.