SOLVED. Post apocalyptic book set in the UK. Spoiler ahead. [s]

[Janae]

Trying to figure out a book title for a friend.
Plot: Boy thinks he is the last boy on earth, enjoys it at first, but then gets sad. He finds a balloon with a note that people are alive, he goes to them to find out they have hung themselves.
It is set in the U.K.
Any ideas of what book this is?

[Bargle]

It's been so long since I've read it, I don't remember the details, but maybe Empty World by John Christopher?

Note to self: correct answer.

[Janae]

Bargle wrote: "It's been so long since I've read it, I don't remember the details, but maybe Empty World by John Christopher?"

Thanks!

[Bargle]

You're welcome. Glad I could help.