Unusual Day by Sandi Toksvig

When Jessica brings her granny into school for 'Unusual Day' Miss Johnson thinks she's got muddled up with 'Family Day'. Her granny may be wearing a tracksuit and trainers, but she still looks like a fairly ordinary granny. However, when 'Unusual Day' is disrupted by a fire next door, everybody discovers just how unusual Jessica's granny is...
Binding: Paperback / softback