Even if theaters started serving marmalade sandwiches, the giddy experience of seeing the witty and whimsical “Paddington 2” could not be any more sweet.

The prospects for “Paddington 2” were grim at the outset. Here is a children’s movie tossed off in the post-holiday doldrums, a sequel to a 2015 British import that didn’t exactly set the North American box office on fire, and jumping studios because its original American distributor, The Weinstein Company, has become a Hollywood pariah.

But Paddington is a bear with a lot of determination and a positive attitude, and his new movie — now safely in the hands of Warner Bros., which handled producer David Heyman’s “Harry Potter” films — turns out to be completely delightful.

The marmalade-loving former orphan Paddington (voiced by Ben Whishaw) has settled into life with the Brown family quite nicely, and the Browns are their usual chaotic selves.

The father, Henry (Hugh Bonneville), is an insurance risk analyst in a midlife funk, while mother Mary (Sally Hawkins) is a children’s-book illustrator seeking her own adventure. Daughter Judy (Madeleine Harris) is a budding journalist, and awkward Jonathan (Samuel Joslin) just wants to fit in. And their grandmother, Mrs. Bird (Julie Walters), keeps an eye on them all. Meanwhile, Paddington is a friend to all in their London neighborhood, with the exception of the crotchety civil-defense warden, Mr. Curry (Peter Capaldi, late of “Doctor Who”).

Paddington’s main desire, as the movie begins, is to get the perfect birthday present for his Aunt Lucy (voiced by Imelda Staunton), back in Peru. His friend Mr. Gruber (Jim Broadbent), the antiques dealer, uncovers a rare pop-up book of London landmarks, and Paddington thinks it would be just the gift for Lucy.

It’s here that the magical touch director Paul King, who helmed the first “Paddington” film, and co-writer Simon Farnaby (who has a cameo as a cathedral guard) first becomes evident. Paddington imagines Lucy’s reaction to the book, and we see a beautiful animation sequence where the 3-D computer-animated Paddington takes Lucy on a sightseeing tour of a paper-cutout pop-up London.

Paddington sets out to earn money to buy the pop-up book, leading to some misadventures in a barber shop and as a window-washer. But before he can buy the book, someone breaks into Gruber’s shop and steals it. Paddington tries to catch the thief, but ends up arrested and jailed as the culprit. He is sent to prison, where his gentle, polite nature seems out of place against such hardened criminals as the growling Knuckles McGinty (Brendan Gleeson).

The real thief, the audience knows from the outset, is the Browns’ neighbor, Phoenix Buchanan (Hugh Grant), a has-been thespian who believes the pop-up book holds the secret to a legendary carnival star’s hidden treasure. While Buchanan seeks the treasure, the Browns search for evidence of Paddington’s innocence, and Paddington adjusts to life in prison — or, more accurately, prison adjusts to him.

Director King fills every frame with warm-hearted humor and wonderfully eccentric, and very British, touches. Whether it’s Grant hamming it up as a vain actor, or Knuckles reading the prison newspaper, the Hard Times, no stone is left unturned if there’s a clever joke to be found under it. There are sly references to “The Great Escape,” Charlie Chaplin’s “Modern Times” and other movie classics — but the nods are unobtrusive, so younger viewers won’t feel left out of the fun.

And there is fun to be had, by the bucketful, throughout “Paddington 2,” as this resourceful bear lands in trouble and works, in tandem with his loving family, to get out of it. The movie is full of bright wit and sincere joy, as Paddington’s innate kindness permeates all around him, providing a weary world just what it needs right now.

★★★★

Paddington 2

The British bear finds himself in big trouble, in this delightfully bright winter surprise.

Where • Theaters everywhere.

When • Opens Friday, Jan. 12.

Rating • PG for some action and mild rude humor.

Running time • 103 minutes.