If you can call three trees a hedge (you said one meter long), then I suppose so. The lack of space will restrict the growth of the beech and you will have a bonsaid hedge but it should grow.

Thank you, this hedge is to give some privacy at a caravan and there is hardstanding so a tub is the only option. I do have two of this tubs so the hedge will be 2 metres long. Will it restrict the growth considerably?

At 10 inches deep, it would very much reduce the height and the amount of watering you would need would be substantial. Why not go for something a little less demanding like Lonicera nitida Baggesons Gold. That would give you a 2 to 3 feet high mostly evergreen hedge.

bonzied like that they would have to come out and have the rootstrimmed every 4 years or so so thiswont work asa tunnel at all. id be inclined to get some nice climbers and as bigger pots as you can get .