Did you keep it well watered during the dry weather? If not, the combination of a dry spell followed by a wetter period can lead to the growth of the tree slowing down then suddenly speeding up again, causing the bark to split. Don't worry though, this is not terribly unusual - it should be okay.

I have kept mine well watered in a draught since it split 2 years ago but this was between where the branches met the trunk and not down so quite different to yours, also the roots can go round and not out in some of these trees if planted wrongly, making it difficult for it to survive in real draught. But I have had no trouble since.

Thanks for the suggestions.It could be due to the drought and then rain...hadn't considered that!Hopefully not too much to worry about then.

I hope someone else will comment on this Pam as my concern with mine was could disease enter the splits or would they self seal? Mine seems fine but yours may be very different?

Oh now I'm a bit worried....hope there is someone who knows.

Its too long a split to be damage from a creature and if its open ??? so why not pm Bamboo and ask her to look at this question Pam?

There is a chance that disease could enter the split, but it will probably form a callus over the wound and heal by itself. If you're really worried I suppose you could paint it with Arbrex Seal & Heal, but I've never used it myself.

thanks for all suggestions I will let you know how it goes.

I got the message, Pam24 - if the split or crack is totally dry and not oozing, I wouldn't worry - I tend to agree with Annies plant on this, both her answers seem appropriate to me. Only other possible cause might be the severe cold last winter, but as you're in London, probably not.

thanks very much, I am reassured! No oozing there so thats good. :)