Thousands of children across the UK are celebrating World Book Day by dressing up as their favourite story characters - or book catalogues.

Celebrating its 19th anniversary, proud parents posted scores of photographs online of their children in their most creative outfits.

From Harry Potter to Where's Wally, the literary world really has come to life.

Oliver Jackson, from Sedgley, West Midlands, as Fantastic Mr Fox Credit: Gemma Jackson
Hazel Shepherd, of Harrogate North Yorkshire, from The Perfect Hug Credit: Jenni Shepherd
Olivia, from Cockermouth, Cumbria, as the Queen of Hearts Credit: Nic Easterbrook

But not all parents remembered it was World Book Day and were forced to improvise at the last minute.

Comedian Joe Heenan took inspiration from the Argos catalogue, although not apparently to his childens' amusement.

Others were simply overwhelmed by the numbers of fictional characters roaming the school grounds.

While children from all over the UK celebrate, World Book Day is marked in more than 100 countries worldwide.

Jake McCormick, from Dumfries, Scotland, as Incy, Wincy Spider Credit: Ash Wynne
Officers arrest the Oompa Loompa in Merthyr Tydfil, south Wales Credit: SWPMerthyr/Twitter
Lilah, from Cardiff, as Harry Potter Credit: Claire Drewen