"For the last 10 years, children have grown up with Harry Potter, " said child psychotherapist Colman Noctor. "The first readers are now in their early twenties and they have built up a real relationship with the books' characters . . . as has everyone who has read them. It will be really sad to see that go and I think there will be an air of depression when the last page has been read."

A recent radio survey revealed that the death of Dumbledore in Harry Potter and the Half-Blood Prince was one of the main events in recent history that made adults cry.

Given that author JK Rowling has promised a "blood-bath" at the end of the final book, Harry Potter and the Deathly Hallows, readers can expect to lose at least some of their favourite characters.

"It will be very upsetting to have your favourite character killed off, and it will probably be especially bad if Harry dies, " said Noctor. "But the beauty of Harry Potter is that, even though it is a fantasy, it has always mirrored real life and taught its readers that life is about loss and about change, but that we can survive and come through it. Characters will die and readers will be upset, but that's life."

There have been several theories as to how Harry Potter will end, with some cynics believing that Harry's story has all been in his head and he has been making it up to escape from the daily drudgery of life with the Dursleys. Others have put out the theory that Harry must take his own life in order to defeat Voldemort.

With the ending leaked on the internet before the book came out and the constant danger of overhearing others discussing the ending, devoted fans will be keeping a low profile until they have finished the book for themselves.

"Although they'll want to find out the ending, people are going to read this book slower than they have read the others, because they won't want it to end, " said Noctor.

"It's been in our lives for the last decade and now that we have to come to the end, it's going to be very hard."