Ant infestation in lawn

[bemused2]

I have a major problem with ants nesting under my lawn. The nests are high and quite large. I once dug a hole and put hosepipe down it and after half an hour i could still hear the water 'glugging' away. It is a nightmare to mow the lawn, it will never be a bowling green as too bumpy now. I tried powders, gels, even boiling water but they come back year after year. Not an expert on ants but we get a lot of flying ants in the summer.
Please help as even the childrens swimming pool cant sit flat on the grass anymore. I really am at my wits end

[muddie]

If your soil is acidic on the pH scale you could trying applying garden lime to your lawn - ants prefer a low pH and the lime will raise it. It wouldn't get rid of them, just reduce the activity.