When the pair leave school, they continue to write until war breaks out, and a letter arrives from Bertie informing Millie that he has joined the army.

British theatre critic Lyn Gardner said in his review of the play that "this is a gripping and ultimately touching couple of hours, made all the more compelling by Daniel Buckroyd's staging ... Buckroyd is as much a storyteller as Morpurgo, and while the narration is initially a little clumsy and overemphatic, and the physical theatre element somewhat overworked, the performances find rhythm and power ... it may be an old-fashioned, nostalgic story, but music, storytelling, design, puppetry and stagecraft come together".

In addition to being a successful adventure story, the book demonstrates the value of character – of keeping promises standing up for one's beliefs, and courage under fire".

[5] Nick Smurthwaite of Design Week said "the combination of Morpurgo's imaginative story-telling and Birmingham's lovingly detailed pictures has proved to be one of the biggest success stories of children's literature in the 1990s".

[6] Publishers Weekly said in their review that the "conclusion is sweet, but unless readers can picture the famous White Horse on the hillside at Uffington, they will have difficulty imagining an adult Bertie and his wife carving out a similar picture of the white lion or blue butterflies alighting on it en masse to drink on the chalk face – concepts critical to the book's conclusion".

[7] In her review for the Booklist, Kathleen Squires wrote "the story sounds hokey, but Morpurgo evocatively captures the South African landscape and presents young, lonely Bertie's heartbreak and his blossoming friendship and love for Millie with genuine emotion and tender poignancy.