It looks like moderate drought damage. If the damage just showed up recently, and the weather has been rainy, I would look for troubles with the roots, instead. One way or another, water isn't getting to those leaves.

Its in a large container and now and again i do forget to water it. Should i be spraying the leaves as well?

Do you think it will be ok next year or has some permanent damage been done?

It will be set back a little, and you will have a little fewer fruit than you ordinarily would next summer, but it should recover otherwise. It is probably a little late for it to show recovery this year, though.

Fruit trees are better off when planted in the garden rather than in containers as watering and feeding will always be critical. Wait until the dormant period and plant out in the garden. The picture that you show looks like leaf scorch rather than lack of water.

Thanks Jimmy for your advice. I dont have enough space to plant it straight into the ground as i have a very small garden and most of it is paved. Is there anything i can do in future to prevent this from happening again and hopefully get some fruit? The container is quite big and i have spring bulbs planted in there as well as some annuals and lilies. Would it do some good to the tree if i pull everything else out? Also what about fertiliser, can i use chicken pellets and whens the best time?

I would pull everything out, and be prepared to prune the tree back just a little if that will break some roots. Make sure that the container is at least 24 inches wide and deep, and leave around 2-4 inches empty at the top to hold water when you soak it. Put about 1-2 inches of coarse mulch on top of the potting compost, to help keep it cool and moist.
Water holding polymer gel granules can be useful. Use a smooth steel rod--available from some hardware stores--to make holes about the size of a standard pencil, about 18 inches deep, and 6inches apart. Using a temporary paper funnel, fill the holes up with the dry granules, and water several times afterward, to saturate them.
If the container is plastic or metal, you can keep the roots at a more even temperatureby putting that container into one a few inches bigger, and filling the space in between with styrofoam packing "peanuts". The top of the "peanuts" can be hidden with anything from bark to stones to Spanish moss.
Unless the tree is grafted onto a dwarfing rootstock, you will have to learn some advanced pruning techniques for yearly reduction of the crown, without losing fruit production. Also, be prepared to prune a portion of the roots every several years. Books on bonsai and espalier techniques will be helpful there.
I hope that all of this helps!

I would suggest that the best idea would be to give the tree to a friend. You will find that to continue with the present situation will prove more trouble than it is worth. If you do need to prune then this must be done when the tree is well into leaf as 'silver leaf' may occur and regular disturbance could let in 'bacterial canker' which will mean close of play for the tree.