Environmental activist Ollie Nancarrow, 18, quipped on Twitter: “Guess who’s been busy today mowing a stiff message for Trump under the Stansted flightpath ... Please share and let’s see how far we can spread the welcome!”

The protest “art” also included a giant polar bear with the message: “Climate change is real.”

A cheeky British high school student carved a giant penis into his family’s spacious lawns to give Donald Trump a big Resistance hello as the president flew into London on Monday. The penis — paired with the words “Oi Trump” — can be easily seen from the air and is just minutes from London Stansted Airport, where Trump landed.

Guess who's been busy today mowing a stiff message for Trump under the Stansted flightpath... Please share and let's see how far we can spread the welcome! #climatechange #Trump #welcometrump pic.twitter.com/crnZo5rnDv

Nancarrow, who runs the online site Born Eco connecting buyers with eco-friendly traders, spent much of the weekend carving out his message just outside Hatfield Heath with the “full support” of his mom and stepdad, reported the Bishop Stortford Independent. He took photos of the final product with a drone to post on Twitter.

Nancarrow told The Metro: “All my teachers have been shaking my hand and congratulating me.”

Trump’s dismissive attitude about climate change — the president has called it a “Chinese hoax” — particularly rankles Brits.

A letter sent Friday to outgoing Prime Minister Theresa May signed by 250 academics from British universities and research organizations blasted Trump’s “refusal” to tackle global warming. His failure to take positive action is “increasing risks for lives and livelihoods” across the globe, the letter warned. May was expected to raise the issue with Trump.

When a Sun reporter asked Trump last week how he would address climate change with eco-activist Prince Charles, Trump insisted: “We have among the cleanest climate in the world.” He also explained that “it is a big atmosphere” and said that not all countries are doing their part to battle pollution.

Twitter fans loved the lawn art.