A controversial “No” sign on famous Irish mountain Ben Bulben is causing a stir ahead of the May 25 referendum on abortion in Ireland.

A gigantic “No” sign has been placed on the north side of iconic Irish mountain Ben Bulben by a pro-life group in Co. Sligo. The mountain was previously the home to political statements such as “H Blocks” and “Brits out” during the Troubles in Northern Ireland.

“It is a massive project and there are about 20 of us on the mountain at the moment involved in the operation. It is well-planned and well-executed, just as the government is planning to execute the future children of Ireland,” said Tommy Banks of the Sligo For Life campaign, adding that men started work on the sign at 4am on Thursday morning while women made tea and sandwiches.

Read more: Cillian Murphy urges men to vote in Ireland's abortion referendum

Those behind the erection of a huge NO sign on Ben Bulben complete their work, insisting they have not broken any laws @OceanFmIreland #loveboth #Together4YES #8thAmendment #sligo #benbulben #leitrim pic.twitter.com/Ob5H8NgWmO

— Niall Delaney (@OceanNWT) May 17, 2018

“We’re just saying no, it’s a big cry from the mountain to say no.”

The sign has stirred controversy by those who think it has defaced the mountain, an iconic Irish sight often featured in the work of W.B. Yeats.

Read more: Irish Americans are taking sides in Ireland’s abortion vote

Meanwhile, the National Parks and Wildlife Service asks for the 'NO' banner on Ben Bulben to be removed. (No doubt someone will point out that the minister responsible for NPWS is also FG's director of elections…) pic.twitter.com/bCDPEd0bhp

— Gavan Reilly (@gavreilly) May 17, 2018

Banks claimed, however, that the land used is commonage and that they had permission from all the landowners to erect the temporary sign.

While there has been general outrage from the Yes campaign about the move, some Irish Twitter users, of course, had to see the funnier side:

Sligo County Council are currently in the process of erecting the lyrics to the county's favourite song on Ben Bulben... pic.twitter.com/GWGIe1rWk1

— JOE.ie (@JOEdotie) May 17, 2018

Someone is currently writing a Giant “NO” on the side of Ben Bulben in Sligo. Someone please go up and change it to “No Duckarsing”

— Rubber Bandits (@Rubberbandits) May 17, 2018

Ben Bulben backs up John Waters #benbulben #benbulbin #repealthe8th #Together4Yes pic.twitter.com/br1VbiZA51

— Hopeless Surfer (@HopelessSurfer) May 17, 2018

Yes campaigners respond quickly to the No sign appearing on Ben Bulben #benbulben #repealthe8th pic.twitter.com/OJygeeP0Kb

— Ken Byrne (@kenb21) May 17, 2018

Do you think Ben Bulben should be used for political purposes? Let us know your thoughts in the comments section, below.