Prime minister Boris Johnson has confirmed that he is the author of a putative blockbuster film script entitled Mission to Assyria, which failed to be picked up by the “distinguished director” it was sent to.

Speaking to the Standard, Johnson said: “I did send it to a very distinguished director, and I’m embarrassed to say that I had no answer back. I was so crestfallen that I didn’t pursue it.” Claiming the script was “absolutely brilliant”, he said he abandoned the idea after seeing an advert for the George Clooney film The Monuments Men. “I thought, ‘Damn, that’s probably my idea.’”

The existence of the script was revealed a week ago by Standard columnist and former Vogue deputy editor Emily Sheffield, Samantha Cameron’s sister, who appears to have been passed a treatment rather than the full script. Describing the pitch as “hilariously awful” and “written in classic Boris prose”, Sheffield quotes sections of Johnson’s work. Writing “I cannot abide the apathy of the west”, Johnson adds that he was inspired by the destruction of large portions of the Middle East’s archeological heritage after the Iraq war to create “a glorious wish-fulfilment dream movie, a mixture of Golan-Globus and Raiders of the Lost Ark”.

Sheffield also quotes in full Johnson’s description of Mission to Assyria’s opening scenes: “We begin with a sickening montage of atrocities: beheadings of innocent people in orange jumpsuits, torchings of Shias, rapes of Yazidi women, and footage of the smashing and the demolition of the Assyrian cities … These bestial crimes are orchestrated by a horrible cologne-drenched jihadi with an air of mincing menace.”

Led by an archeologist called Marmaduke Montmorency Burton (“an old Clooney/Connery/Eastwood type geezer in his fifties”), a seven-strong team of explorers aims to save “Shargar, the long-lost city of Tiglath-Pileser III in Syria, from the advancing evil of Islamic State”. Johnson suggests Angelina Jolie or Scarlett Johansson for the female lead, and describes enemy jihadis as being “spifflicated” with shovels.

Released in 2014, The Monuments Men stars Clooney as the leader of a team of academics who recover art works looted by the Nazis during the second world war.