AUSTRALIA would have experienced 15 terror attacks including public beheadings on home soil over the past three years if most plots in their advanced stages hadn’t been foiled, according to police.

The terror attacks police were unable to prevent include the Lindt Cafe siege in Sydney in which manager Tori Johnson and mother-of-three Katrina Dawson lost their lives; the killing of police accountant Curtis Cheng by 15-year-old schoolboy Farhad Khalil Mohammed Jabar in Parramatta and the non-fatal stabbing of Wayne Greenhalgh in Minto last year. In Victoria, Numan Haider, 18, attacked two police officers with a knife outside the Endeavour Hills police station before being shot dead in September 2014.

Among the alleged “imminent” terror plots foiled by police in the last two years were advanced plans to kidnap members of the public in Sydney and Brisbane then behead them on camera and release the footage; detonate bombs at a Mother’s Day running event; stab and shoot police and members of the public at Anzac Day ceremonies; and target government buildings including the Garden Island Navy base and Parramatta Court House.

Before this weekend's raids in Sydney, the most recent plot to be thwarted in NSW allegedly involved two 16-year-old boys who purchased knives and were en route to behead a stranger in Sydney’s Bankstown before they were arrested.

NSW Police deputy commissioner Catherine Burn claimed at the time it was the “11th imminent attack ... we have prevented in this country”.

“There have been four attacks, three have been in NSW,” Ms Burn said.

“While we cannot necessarily guarantee that attacks won’t occur, we know that the processes and what we are currently doing, we are doing everything we can to prevent such attacks.”

A recent US Homeland Security report revealed that Australia ranked equal third among Western nations as a target for Islamic State-inspired terror attacks.

The likelihood of Australia suffering another terror attack is “probable”, as ranked on the National Terrorism Threat Level.

“Credible intelligence, assessed by our security agencies indicates that individuals or groups have developed both the intent and capability to conduct a terrorist attack in Australia,” according to Australian National Security.

Here are some of the most recent alleged “imminent terror attacks” Australia has narrowly escaped:

PLOT: BOMB MELBOURNE'S MOST PROMINENT SITES

DECEMBER 2016

Four men were charged in what authorities allege was a plot to launch a Christmas Day terrorist attack targeting Melbourne landmarks including Federation Square and Flinders St Station.

PLOT: BEHEAD A MEMBER OF THE PUBLIC IN SYDNEY

October 2016

Two schoolboys who were allegedly preparing for a terror attack in Sydney’s southwest, with police alleging they had links to the Islamic State, were arrested and refused bail on Wednesday.

The 16-year-olds were detained in a laneway behind a Bankstown mosque about midday, hours after they allegedly bought two bayonets at a local gun shop.

Police wearing protective vests headed to the prayer hall after officers received information about the alleged purchase of the knives. The pair allegedly also had pieces of paper with religious statements on them, which the Daily Telegraph reported they planned to read out while they carried out a beheading.

Police said the students may have been influenced by “radicalised peers”. One is related to a convicted terrorist and refused to stand for the national anthem at school two years ago.

PLOT: DETONATE EXPLOSIVES IN MELBOURNE

August 2016

Operation Fortaleza disrupted an alleged domestic terrorist attack at an undisclosed location in Melbourne, potentially involving improvised explosive devices.

PLOT: STAB A NSW POLICE OFFICER TO DEATH

June 2016

A Sydney teenager allegedly planned a “serious” terror attack — potentially involving a knife — on a police officer in NSW.

The 17-year-old was charged with a “terrorism-related offence” after police were alerted to a series of social media posts where the teen had threatened to kill a police officer.

He was charged with planning a terrorist act and using a telecommunications network to commit a serious offence, police said in a statement.

NSW Police Commissioner Andrew Scipione told media the teen “talked about ... killing a police officer” in the post.

“It talked about hurting a police officer, in fact killing a police ... officer,” Mr Scipione said.

Mr Scipione said the individual “indicated he proposed to act in the very, very near vicinity in terms of time”.

“He was allegedly going to conduct any act within a very short period of time,” he said.

PLOT: ACQUIRE FIREARM AND SHOOT CIVILIANS IN SYDNEY

May 2016

A Sydney man, 18, who had allegedly bid to join extremists in Syria, was accused of planning an imminent lone-wolf terror attack in Australia.

Attorney-General George Brandis said authorities had not acted until relatively late so more evidence could be gathered.

The man was “in the process” of acquiring a weapon, he told reporters.

“The judgment of the police was that he was intending to put it to use imminently,” Mr Brandis said.

He had allegedly been scouting out possible sites in Sydney to carry out the attack.

PLOT: BEHEAD A POLICE OFFICER & SHOOT CIVILIANS ON ANZAC DAY

April 2016

Sevdet Ramadan Besim, 19, pleaded guilty to a plot to run over and then behead a police officer before using his gun in a bloody rampage, after his plan was foiled.

A court heard he used an encrypted messaging app to try and obtain a gun to “terrorise” the “kafirs” on Anzac Day.

He allegedly wrote he was “ready to fight these dogs on there (sic) doorstep” in online communications with a person overseas, according to court documents.

“I’d love to take out some cops,” Besim is alleged to have written.

“I was gonna meet with them then take some heads ahaha.”

Besim was in regular communication with a teenager in the United Kingdom, who encouraged him to not only carry out the Anzac Day attack, but to break into someone’s home “and get your first taste of beheading’’.

Crown prosecutor Chris Choi said Besim, an electrical apprentice, tried to obtain a gun for an Anzac Day attack and, when that failed, a bomb manual.

He said he targeted April 25, “because here in Australia the kafir (non-Muslims) celebrate Anzac Day and I want to terrorise them on that day”, Ms Choi said.

He sent a text on April 16, “I want to learn how to make a bomb”.

The Islamic State flag appeared in his messaging avatar, Ms Choi said.

The Hallam teen was handed a 10-year jail sentence in the Victorian Supreme Court in September 2016 and must serve at least seven and a half before he is eligible for parole.

Police said he was motivated by an extremist ideology and had expressed support for terrorist organisations, particularly Islamic State, which adopt a radical interpretation of Islam.

PLOT: TARGET PARRAMATTA WESTFIELD

Jan-Feb. 2016

One of two accused terror plotters who allegedly planned to carry out a terror attack at Parramatta Westfield was found with a hunting knife and a Shahada flag in her handbag as well as instructions for making a bomb detonator. The teenager laughed and cheered as a Sydney court heard evidence of her “favourite” beheading video.

PLOT: BOMB MELBOURNE’S MOTHER’S DAY CLASSIC EVENT

May 2015

A teen terrorist who planned to detonate bombs at a Mother’s Day event in Melbourne described all non-Muslims as cockroaches.

Police raided the teen’s home on May 8 after he began messaging radicals overseas that he would become a martyr.

Counter-terrorism officers found IS propaganda material, pressure cookers, pipe bombs, shrapnel and homemade explosive that the teen now admits were to be used in a bombing.

“I thought that a lot of (Australian) people were not innocent because they were supporters of the killing of Muslims around the world,” the teen allegedly said.

PLOT: KILL POLICE AT ANZAC DAY CEREMONIES

April 2015

Aspiring terrorists allegedly planned to run over a police officer, kill him with a knife and seize his gun before going on a shooting rampage during Anzac Day centenary celebrations in an attack foiled by a police operation.

The group behind the alleged plot had reportedly anticipated the attack on Melbourne streets would end in their own deaths.

Australian police arrested five teenagers in Melbourne over their alleged plans to target police uncovering knives and other weapons in their raids.

ALLEGED PLOT: TO BEHEAD INNOCENT PEOPLE

February 2015

Two Sydney friends were arrested just hours before they planned to carry out a terror attack.

Omar al-Kutobi, 24, and Mohammad Kiad, 25 were accused of planning to carry out an attack, amid suspicions they were plotting a public beheading.

A machete, a hunting knife and a flag associated with Islamic State were among items seized in the raids on their Fairfield home, along with a video of Al-Kutobi holding knives and vowing to stab white people in the kidneys and necks “today” with a note declaring he and Kiad “are here to cut your head”.

Less than a week before they were due to face trial, the pair pleaded guilty in the NSW Supreme Court to one count each of “to act in preparation/planning for terrorist act” .

PLOT: TARGET GOVERNMENT BUILDINGS

December 2014-March 2016

A Sydney teenager accused of plotting an “imminent” terrorist shooting in Sydney had allegedly scoped out the Parramatta court complex, Garden Island Navy Base and the Victoria Barracks before he was arrested as part of Operation Appleby.

The original plot involved alleged planning of an attack on a random member of the public. Police said the second plot “may have involved an attack on a government building, whether that be AFP or police”.

PLOT: KIDNAP INNOCENT PEOPLE IN SYDNEY & BRISBANE THEN BEHEAD THEM ON CAMERA

September 2014

An accused terror plotter was within days of launching a terror attack on Australian soil, embarking on a frenzied, deadly shopping spree to load up on weapons, before he was arrested, police alleged.

Police said the man planned to launch a terror attack on home soil.

Government officials revealed that the plan was to kidnap random members of the public, behead them on camera and then release the video of the killings.

The man was charged with transporting a gun and stockpiling machetes, knives and balaclavas, military clothing and a firearm in preparation for a terrorist act.

The public should continue to exercise caution and report any suspicious incidents to the National Security Hotline by calling 1800 1234 00. Life-threatening situations should be reported to the police by calling triple-0 (000).

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megan.palin@news.com.au