I don't actually know, but thought I'd offer my sympathy and hope this has some type of positive outcome for you. I hate when trees are destroyed in the name of "home improvement". The ambience of trees is often the very thing that draws people to an area in the first place.

Slap a tree preservation order on it? However, you don't want to get into your neighbours bad books. Have a chat with the local tree preservation man at the council. He may be able to reassure you (or not!) but if this wasn't pointed out when planning permission was being sought, there may be nothing you can do but hope that it survives. Look after your side of the tree by feeding and watering it well. Get onto the builders to try and limit damage whilst the work is going on and don't let them break off branches that are in the way. Good luck.

If you haven't lodged an objection to the planning permission, do so immediately, on the grounds that it threatens your tree's survival. Most Councils take damage to trees seriously, and will certainly take this into consideration. It doesn't mean they won't get permission, but it might mean they have to take measures to ensure your tree survives.

Is there any info on the variety that might make it particularly worth preserving? (I don't mean in jars, but as a tree!). I've looked it up, but can't find anything yet which sets it apart from many other varieties. It's a old variety, certainly, and by all accounts, well thought of in the fruit tree stockists' circles. Perhaps if it was an old 'heritage' type variety, that might carry some weight with the local council, and assist the tree officer with his decision to protect it. Phil J