The pranksters from The Chaser have waded into the controversy around the Sydney Opera House being used to promote The Everest, a horse race. Last night the serial provocateurs projected controversial 2GB radio broadcaster Alan Jones’s phone number onto the iconic sails in response to an on-air interview where Jones attacked Sydney Opera House chief executive Louise Herron for being opposed to having the advertising on the Opera House sails.

In a one-minute video of the Monday night event posted to social media, Chaser member Charles Firth drives up to a security guard stationed at a roundabout at the entrance of the Opera House. His vehicle has a large projector attached to the top of it.

“Just got a projector – just going up there to the Opera House. Alan called your boss ... It’s all fine,” he says in the video.

After being refused entry by the security guard, Firth turns his vehicle around to exit the roundabout – but not before projecting the words “Advertise Here: Call Alan” onto the Opera House sails, followed by what is purportedly the shock jock’s personal phone number.

Urged to hurry along by the security guards, Firth says, “You’re allowed to project onto there. That’s the biggest billboard in Sydney,” echoing the words of Prime Minister Scott Morrison, who said the Opera House is “the biggest billboard Sydney has”.

Earlier in the video Firth drives past other Sydney landmarks, such as the Art Gallery of New South Wales and parliament, and projects his message across their facades.

Further opposition to The Everest promotion on the national landmark is expected tonight, when an anticipated 3300 people will converge at Bennelong Point to stage a “light-based protest”. A petition in support of Louise Herron – who resisted Racing NSW’s calls, and Jones’s demands, to project the barrier draw of The Everest race onto the heritage-listed venue but who was forced by the NSW Government to go ahead with it in the end – has more than 252,000 signatures.

This morning, Jones made a public apology to Herron for on-air remarks he made to her on his Friday breakfast program. In the heated on-air exchange, Jones called for the chief executive’s resignation if she continued to deny promotion of the horse-racing event.