The Ice Monster by David Walliams. Ages 8+.
The Ice Monster (2018) is set in Victorian London in 1899. Elsie is a ten-year-old orphan living on the streets. When a woolly mammoth — perfectly preserved in ice — is brought to the Natural History Museum from the Arctic, Elsie becomes obsessed with it. She befriends the real explorer Lady Buckshot (based on Lady Florence Dixie) and, after a series of misadventures, finds herself on a voyage to the Arctic to return the mammoth to its home.
The novel blends comedy, adventure and a genuinely moving friendship between Elsie and the mammoth. The Victorian setting is richly detailed. The ending, in which Elsie must choose between what she wants and what is right for the mammoth, is one of Walliams's most mature.