Former South Australian opposition leader David Speirs has confirmed he will leave parliament and suspend his Liberal Party membership after being arrested for drug offences. 

Mr Speirs made the revelation in a more than four minute long video he described as the hardest he has "ever recorded", which was posted to social media on Saturday. 

"Since allegations of illicit substance use in my home became public, my home has been raided by armed police and I was arrested and I was questioned," Mr Speirs, who quit as the state Liberal Party leader in August, said.

"I believe there's someone pretty sinister behind this and while I am personally devastated by what has happened and I will fight to clear my name of any allegations, I'm equally concerned about what is actually the use of state government power against someone who is a political opponent."

Mr Speirs' social media post prompted South Australia Police to issue a statement confirming they had arrested him last month, and searched his home.

"As a result of the public statement made on social media by MP David Speirs in which he reveals he had been arrested, police can confirm that on September 26 2024 Mr Speirs was arrested at Berri and charged with two counts of supplying a controlled substance between August 2 and 3 and on August 9," police said.

"Following this his residential premises was subsequently searched. Mr Speirs was given police bail and will appear in court at a later date."

Mr Speirs, the Member for Black in Adelaide's southern suburbs, said he will resign from parliament in the next sitting week, which is scheduled to commence on October 15.

"I don't believe that I can adequately and effectively serve my local community while also dealing with this matter and protecting my mental health and supporting my family and friends," he said.  

"For me it's time to move on. I want to rebuild myself over the coming months and into the future. To be honest, I want to be a better person.

"That will take time and I believe it's best done away from public life. A such I do intend to step down formally from parliament in the next sitting week.

"I've informed the state Liberal leader and the party. I'm going to suspend my membership while I seek to resolve this matter but I certainly remain committed to, and true to, Liberal values, and the cause of the Liberal Party."

During the video, Mr Speirs also spoke about how "the last few months have been really incredibly challenging for me".

"That culminated in me leaving the leadership of the Liberal Party in August. I have endured many pressures over the last few months, if not more," he said.

"My mental health has been in significant decline. I've not been the best version of myself. And I have spent time with people who did not bring out the best in me, to be quite honest."

Mr Speirs stepped down as Liberal leader on August 8, declaring he "had a gutful" of the role which saw him grapple with the rebuild of the Liberal Party after it was turfed out of government by the Peter Malinauskas-led Labor Party in 2022.

"I just do not have the energy at this stage or in fact the want to continue in this role and take the party to 2026," he said at the time.

Scottish-born Mr Speirs was first elected to parliament in 2014 as the Member for Bright.  

Mr Speirs said on Saturday he would step down later in October after police arrested him and raided his home. 

Police later confirmed the 39-year-old was arrested at Berri on September 26 and charged with two counts of supplying a controlled substance between August 2 and 3 and on August 9.

"Following this his residential premises was subsequently searched," they said.

Mr Speirs was granted bail and will face court at a later date.

The police statement followed Mr Speirs' post on social media announced he would formally step down as the member for Black, in Adelaide's south, when parliament resumed on October 15.

"Since allegations of illicit substance use in my home became public, my home has been raided by armed police, I was arrested and I was questioned," he said in a video.

Mr Speirs said he did not believe he could "adequately and effectively serve my local community while also dealing with this matter, protecting my mental health and supporting my family and friends".

He said he would suspend his Liberal Party membership and thanked his colleagues for their support.

"For me it's time to move on, I want to rebuild myself over the coming months and into the future," Mr Speirs said.

"I want to be a better son, I want to be a better friend, to be honest, I want to be a better person.

"That takes time, and I believe it's best done away from public life."

Mr Speirs resigned as opposition leader on August 8 and was replaced by Vincent Tarzia, who said on Saturday the party's state executive had ratified the suspension of Mr Speirs' membership.

The party respected Mr Speirs' decision to quit, Mr Tarzia told reporters.

"It's obviously a very hard, challenging decision for him," he said.

"I know he hasn't made that decision lightly."

Standing down was in the interests of Mr Speirs own mental health and welfare, "but also in the interests of his community and the parliament", Mr Tarzia said.

He said the party now focused on preselecting "the best candidate we can" to hold the seat of Black, which Mr Speirs has held since 2018.

The Arrest and Charges

David Speirs was arrested on September 26, 2024, at Berri, South Australia. He was charged with two counts of supplying a controlled substance between August 2 and 3 and on August 9. Police searched his home in Kingston Park after his arrest.

Speirs was granted bail and will appear in court at a later date.

Speirs's Resignation

Speirs announced his resignation from parliament in a video posted on social media on Saturday. He said he did not believe he could adequately serve his community while dealing with the charges and protecting his mental health. He also said he would suspend his membership of the Liberal Party.

Speirs stated that he intends to step down formally from parliament in the next sitting week, which is scheduled to begin on October 15. He expressed his commitment to Liberal values and the cause of the Liberal Party, both at state and federal levels.

The Liberal Party's Response

The Liberal Party has accepted Speirs' resignation and will be seeking a new candidate for the seat of Black. The party's state executive ratified the decision to suspend Speirs' membership.

Vincent Tarzia, the current leader of the Liberal Party in South Australia, said the party respects Speirs' decision and that he knows Speirs did not make the decision lightly. He also stated that the party is focused on finding the best candidate to hold the seat of Black.

Conclusion: A Fall from Grace

David Speirs's fall from grace is a stark reminder of the high stakes involved in politics and the personal toll it can take. His story is a cautionary tale about the importance of mental health and the need for politicians to prioritize their well-being in the face of intense public scrutiny. Speirs's arrest and subsequent resignation have also raised questions about the use of state government power in political matters. While Speirs's decision to resign was likely driven by personal reasons, it is undeniable that the drug charges and the public scrutiny that followed have brought his political career to an abrupt end. His story serves as a reminder that even the most successful politicians are not immune to the pressures of public life and the consequences of their actions.