Lysimachia - someone here is probably able to tell you the variety as well.

Im not usually good at i.d's but i do know this is yellow loostrife, ive seen a question on this same plant the other day ,it is lovely tho. ;)

Does it attract insects?

Lysimachia punctate is the species and the open flowers are very good at attracting bees, hoverflies and other night flying moths.

Yes lysimachia punctata, its a beautifull clump forming perennial, yes it does well in pots and great in the border, however this really does increase in size very quickly, does better in a larger pot as in a smaller pot with other perennials it will become invasive and take over, each stem you have now will increase to aprox four each year so you can see how quickly it can take over, a very hardy and robust perennial a great performer, look out for lysimachia clethroides if you can, a real real eye catcher.

Thank you for all your replies, I have just found this site and I am really impressed!