Nanny McPhee and the Big Bang (released in the United States and Canada as Nanny McPhee Returns) is a 2010 period fantasy comedy film directed by Susanna White, produced by Tim Bevan, Eric Fellner and Lindsay Doran with music by James Newton Howard and co-produced by StudioCanal, Relativity Media, Working Title Films and Three Strange Angels.

When the children's wealthy but pompous and snobby city cousins, Cyril and Celia, are evacuated to live with them in the countryside, they start fighting, only adding to Isabel's problems.

He sets loose the litter of piglets to be sold to a neighbouring farmer, but the plot is discovered by the children, leading them to bond as they work together to fix it.

Isabel takes everyone on a picnic as a show of thanks, during which Mrs. Docherty's ARP Warden husband warns them about bombs and relates how he imagines a pilot might accidentally release one.

They convince Nanny McPhee to take them to the War Office in London, where Cyril and Celia's father Lord Gray holds an important position, believing he will know the truth.

While the older boys are at the War Office, Megsie, Celia and Vincent try to stop Isabel from signing Phil's papers and selling the farm by creating distractions, such as pretending that a mouse was in the kitchen.

Finally, as she is about to do so, a German pilot accidentally drops a huge bomb on the Greens' barley field; it does not explode, but the impact is strong enough to cover Phil's papers with ink.

In a mid-credits scene, Ellie, an elephant conjured by Nanny McPhee to share Vincent's bed, is seen enjoying the magically operated Scratch-o-matic invented for the piglets.

Nanny McPhee Returns, as the film was renamed for the North American market for undisclosed reasons, was released on DVD and Blu-ray on 14 December 2010.

The site's critical consensus reads: "Emma Thompson's second labor of love with the Nanny McPhee character actually improves on the first, delivering charming family fare with an excellent cast.