How big is the pot you have in mind, Olympic? It could make a difference to what could be grown. And where in the country are you? That could make a difference, too. There will be lots of suggestions once we know, I'm sure.

Stand your pot on feet and put a bit of weed suppressant fabric or a bit of J cloth over the holes before planting that will help keep ants out. Also they hate the wet so choose a plant that likes water/damp conditions.
But I agree what do you call a large pot?

First, ants don't eat plants. They may make a nest inside the pot, and destroy plant roots because they're in the way, otherwise, if they're running over plants, its because there's an aphid infestation and they're collecting the honeydew the aphids produce. Treat for aphids and the ants go away.
Secondly, as Ojibway asks, where are you in the UK, and is the pot in sun or shade or half and half? How deep and wide is the pot?
Thirdly, if you suspect there's a nest inside the pot, you need to turn it out and get rid of it, clean the pot and follow Drc's advice with the jeycloth in the bottom before filling with fresh compost. Then stand on something so its slightly off the ground, and dust the ground beneath with ant powder periodically.

Thank you for the advice, i live in hampshire, the pot is in partial sun and is 3ft tall and approx 15" wide. I have emptied the ants nest and ready to start again. olympic.

My, that is a lovely large pot. You could use Pieris Forest Flame, or Pieris japonica variegata - these are evergreen and the new growth on the leaves is bright red when it first appears. They also flower, and the variegated one looks good all year round. Likes acid soil though, so you'd need ericaceous compost. Plant with 1 or 2 small Hedera helix variety ivies to trail down the pot, add pansies for winter, busy lizzies or any other summer bedding of your choice plus trailing lobelia for summer. You would need to heave out the ivies periodically, certainly bi yearly, chop their roots back and pull them apart to make smaller plants, and replant one section of each, otherwise they'll take over the whole pot.