LONDON — The Banksy appeared the way Banksy murals often do: overnight, unsigned and to everyone’s complete surprise.

Before the artist claimed credit, this north London neighborhood was embroiled in a full-on whodunit.

Was it truly the world-famous, elusive artist who had painted streaks of bright green paint that appeared as if they were foliage behind a large tree? Were there telltale signs of his work in the portrait of the young person holding a pressure sprayer on the peeling wall?

By the gray and rainy Monday morning, this normally sleepy corner of Finsbury Park had turned into a circus. Journalists and local politicians descended on the scene after the mural appeared Sunday. A Banksy expert rushed over and declared it to be the likely work of the artist. Neighbors shared photos in chat groups; an unusual crowd gathered to snap selfies and give interviews to journalists.

There were other questions aside from the mural’s provenance. What would it mean for the neighborhood? The Banksy work appeared on a wall just off Christie Court, a block of housing run by the local authority in the borough of Islington, where poor and working-class families live alongside very wealthy residents. “Banksy came overnight and now my rent will skyrocket,” one person posted on social media with an upside-down smiling face emoji.

Then, of course, there were questions about the meaning of the artwork itself.

“It’s been done for a purpose: to get people talking, to get people interested,” said Jeremy Corbyn, the member of Parliament who represents Islington North and a former leader of Britain’s Labour Party, who arrived near the mural on Hornsey Road around 10:30 a.m. and was immediately flocked by cameras and curious constituents.

But talking about what, and interested in what? Banksy’s anti-establishment street art has achieved global notoriety in recent years, and curiosity about the artist himself has lent an aura of mystery to his work. However, Banksy rarely — if ever — explains the meaning behind his street art, letting audiences interpret it for themselves. This makes reaching a definitive conclusion about any work by Banksy a tricky task.

Banksy’s own pictures of the work had no caption on social media.

“It’s typical Banksy,” said Jenna Edwards, 31, a local resident who came to see the mural when she heard about it around the neighborhood. Edwards thinks it’s a symbol of unity. “No matter if the branches and the leaves fall off, as long as you address the root, and we all come together, then we can grow back better,” she said of the tree and its painted foliage.

Jonathan Ward, 55, a local resident and community activist, believes the mural carries an environmental message. Ward said the young person painted on the wall “seems to be holding a weedkiller spray,” in what could be a reference to the “damaging effect” of products such as glyphosate.

Some observers noted that the paint’s shade of green is similar to a shade used by Islington Council, the district authority in charge, in street signs. Yet others said it was a reference to St. Patrick’s Day, which was Sunday.

Rafael Schacter, an associate professor of anthropology and material culture at University College London, said in an email that the mural was “one of the best Banksy works I’ve seen in a while” and that it felt “genuinely site-specific.”

“The brutally pollarded tree against the plain side wall of the adjacent building it sits against provides a really perfect backdrop,” he said, speculating that the work was a statement on the debate about how to best maintain and care for trees. He said the use of color and technique “in which hand-pumped garden pressure sprayers are re-purposed to paint graffiti — something similarly done with fire extinguishers — is a nice touch in term of the relation to … their use in gardening, often for weeding.”

It quickly became an attraction. A group of 23-year-olds heard about the mural that morning and came to have a look. “It’s the first time I’ve ever seen [a Banksy] in the flesh,” one said.

In a local coffee shop and bakery called Jolene, the barista told patrons about the mural as she handed them their coffees, directing them to the right spot. Young people working on their laptops talked about who they thought did it.

In recent years, public pieces by Banksy have at times sparked extreme reactions in the communities where they have appeared: Last year, The Washington Post reported that the district council in Margate, a seaside town in eastern England, dismantled an installation by Banksy timed for Valentine’s Day — prompting an outcry from residents who called it overreach by their local government at the expense of art that could draw tourists to their town.

And in December, two people were arrested after a piece of Banksy’s work — a London stop sign adorned with what appeared to be drones — went missing.

Islington Council told The Post in an email that its “graffiti removal team is aware of the artwork” by Banksy “and won’t remove it.”

The mural “has sparked a real buzz across Islington and beyond, and we very much want the artwork to stay for people to enjoy,” said Roulin Khondoker, executive member of Islington Council for equalities, culture and inclusion, in the email. “We want to find more ways that we can tell important stories through art and culture.”

Adela Suliman and Anumita Kaur contributed to this report.