Thanks, everyone . . . for this sad but necessary news!

It seems my hopes of the thing sprouting with new needles in around its
trunk from top to bottom was a pipe dream and I will only be left with a
chopped and leafless skeleton.

The next best option would be to move it, but what you say about the
likely size of the root-ball rules out any thought of moving it, for it
was planted right beside the decking that surrounds the house! About a
third of its roots will have tunnelled their way under the decking,
making their way towards the foundations of the house.

I hate destroying any plant or tree . . . but sometimes there's no
option.

The only good thing is that cutting it at the base won't be too
difficult if I do it now.

Anyway, thanks everyone for the help! I've been meaning to post this
question for months now. Finally got round to it on New Years Eve!

Happy New Year.

Eddy.