Sounds like sooty mould has set in following a very heavy infestation of aphids or scale insect or both. 30 foot of tree is a lot to spray (with an insecticide and fungicide) which is about the only thing which might make a difference, but if you can't manage that, the tree will recover for next year, it won't kill it. One of the problems this year is the lack of ladybirds, which predate aphids. After the recent heat, we've ended up with an explosion in the aphid population without anything much about to eat them.

Thanks for that. I notice it also has fungi growing up the trunk (about 2-3 feet of fungi) would that also suggest soot mould ? I have now sprayed the lower branches and the surrounding bushes. Relieved to hear it won't kill the tree - the resident pigeons will be pleased !

Fungi up the trunk, hmm, don't like the sound of that. If its a bracket fungus, its not good news for the tree.

Actually the fungus has also gone black and dry and looks like its dead or dying. Is that bad ?

Not necessarily, but it would be very useful to see a photograph. Was it bracket fungus, or actual small mushroom type things? And how far up from the ground were they?

I will take a pic so you can see. I also noticed this morning when spraying an inch hole in the trunk with sawdust in it and a creature pushing the sawdust out. It was too high to see what it was but looked like the front of a spider or something similar.

have added 4 photos showing the fungi and the leaves.

I've added 4 pics so hopefully you can make them out ok ?

Sorry its taken me a while to get back to you. I've had a look at the pics, specifically of the fungal growths. I'm wondering whether they've only gone black since they started dying off (these are just the fruiting bodies of fungal threads within the tree itself), but it doesn't look good to me. The presence of fungal plates on the upper parts of trees means the tree has been invaded by a fungal infection - eventually, the tree will weaken and die, and what you've got to watch for is limbs falling off when you least expect them to, or the whole thing falling over. I'd recommend you either remove the tree completely, or have it checked over by a reputable tree surgeon or arboriculturalist.

Thanks for coming back to me and we will take your advice and get someone in to have a look. Thanks very much for all your help and advice it is much appreciated.