Troy Buswell has resigned from Cabinet, with the Premier revealing this morning that his Treasurer was in a "poor state of health" in a Sydney clinic.
Colin Barnett told a press conference this morning that Mr Buswell had called him to resign yesterday afternoon.
Mr Barnett was responding to revelations this morning that Mr Buswell crashed his ministerial car after hours drinking at a wedding.
The Premier said Mr Buswell's chief of staff had told him earlier that "Troy had had a breakdown".
He had spent about a week in hospital and then several days in a clinic in Sydney. He is still under medical care.
It was revealed overnight that the Treasurer and Transport Minister had crashed his Holden Caprice in the early hours of Sunday, February 23 - the day before Mr Buswell went on personal leave.
This morning the Premier said Mr Buswell had "little memory" of the car crash and said he was in a "state of very poor health". He said he only heard about the Subiaco incident early yesterday afternoon.
Police were at the home of Mr Buswell this morning.
A spokeswoman for Police Commissioner Karl O’Callaghan said that the Commissioner first found out about the alleged driving misdemeanour involving Mr Buswell after media queries to his office yesterday.
He then informed Police Minister Liza Harvey.
The spokeswoman said the responding officers “were not aware of the identity of the alleged driver and no contact was made with the alleged driver”.
Mr O'Callaghan told a press conference this morning that police had received a complaint about an "alleged drink driving offence".
Officers who responded to the call did not know Mr Buswell was possibly involved and that there was nothing linking Mr Buswell to the car or the house.
The car is not registered to Mr Buswell and the residence is not in his name, Mr O'Callaghan said.
He said it was unlikely Mr Buswell will be charged with drink driving.
Officers visited the property on February 23 after a witness complained to police, and inspected damage to the car and gate.
They decided not to pursue the matter as officers found the house dark and no offence was being committed when they arrived.
Mr O'Callaghan says the incident is still being investigated but it's unlikely Mr Buswell will be charged as drink driving charges can't be laid without a breath test.
Opposition Leader Mark McGowan said any police audio, notes, emails and State security unit information relating to the driving incident should be released immediately.
He said ministerial officers in the offices of Mr Barnett, Mr Buswell and Police Minister Liza Harvey should say what they knew about the incident and when.
“I think there is a cloud of doubt that hangs over the Premier’s explanation,” he said.
“A doubt over who knew what and when.
“I think anyone who knew anything about these issues inside the Government should have revealed it to the Premier and the Police Minister. That would have been an appropriate course of action and frankly, I would be surprised that they didn’t or if they didn’t.”
Mr Barnett said he was disappointed Mr Buswell had not informed him earlier of the driving incident but “I think we have to bear in mind that Troy was in a serious state of poor health”.
He said it would be “entirely a decision of the police” if they pursued it.
“My concern now is Troy’s welfare. I think it’s a very sad day, it’s a sad situation he finds himself in,” the Premier said.
He said was not qualified to speculate on whether his health condition was related to the driving incident.
Mr Barnett said he would be officially sworn in as treasurer and transport minister temporarily until a new minister could be added to Cabinet, “maybe by the end of the week”.
“I will endeavour to ensure that any changes to portfolios are kept to an absolute minimum,” he said.
Mr Buswell attended a wedding reception at Kings Park on Saturday, February 22. Guests said he was drinking throughout the evening.
At 1.28am the next day, a member of the public called the WA Police Assistance Centre to report that a white Holden Caprice was being driven erratically on Roberts Road, Subiaco.
The witness, who contacted The West Australian and Seven News this weekend, said the car was perpendicular to the kerb.
It was obstructing the left lane of Roberts Road, near the carpark at the south-eastern corner of Patersons Stadium, forcing the witness to stop his vehicle to avoid a collision.
The Caprice already had damage to its front end.
The witness said the Caprice then veered across from the left to the right lane, nearly colliding with parked cars.
It then pulled into the driveway of a Roberts Road property that is Mr Buswell's Subiaco home.
The witness then saw the driver, wearing black dress pants, a white "tuxedo-style" shirt, no tie or jacket and glasses, "fumble around" with the keypad on the front fence and gate.
"He looked like he was under the effect of something," the witness said.
He then got back into the Caprice, accelerated forward, hit the front fence and spun the vehicle's tyres. The driver reversed before successfully navigating the car through the gate into the driveway.
This morning Mr Barnett said Mr Buswell would continue as the member for Vasse.
He said he would assume both Mr Buswell’s portfolios for the immediate future.
Mr Barnett asked members of the public and the media to "respect Mr Buswell’s privacy at this time".
“Troy has made an enormous contribution to the State of Western Australia in a number of ministerial portfolios and as Treasurer,” the Premier said. “I wish him the very best for the future.”
Mr Barnett said he "honestly" thought Mr Buswell would return to work and at the time didn't realise how serious his health issues were.
"Maybe it all became too much ... I care for Troy as a friend and I hope he makes a recovery," he said.
Yesterday, the Caprice - believed to be Mr Buswell's ministerial car - was in the driveway of his Subiaco home, with damage to the front bumper, which lay on the ground in front of it. Slight damage to the front fence was also evident, with three vertical metal bars bent.
Yesterday a spokeswoman for Mr O'Callaghan said: "WA Police can confirm that the Police Assistance Centre received a call at 1.28am on February 23, 2014, regarding a traffic matter on Roberts Road, Subiaco. A Traffic Enforcement Group vehicle attended the location shortly after. No further information will be provided at this time."
It is not known whether police spoke to Mr Buswell at the scene or subsequently.
The day after the traffic incident, Mr Buswell did not appear at the regular Monday Cabinet meeting and he has since been on personal leave.
Last Tuesday, Mr Barnett said Mr Buswell's leave was "health related" and he called for privacy. Mr Barnett, who is acting as Treasurer and Transport Minister in Mr Buswell's absence, has said Mr Buswell would return to work at the end of this week.
Mr Buswell's political career has regularly been plagued by turmoil.
Only last month he settled a very public defamation case against former lover and former Greens MP Adele Carles. Ms Carles had earlier accused Mr Buswell of "dry-humping" a Perth businessman at a party.
Mr Buswell revealed his affair with the then Fremantle MLA in 2010 and resigned as treasurer when the relationship was made public.
In February 2011 when he was transport minister Mr Buswell admitted to being fined nine times for speeding in just three years.
In 2008 he was forced to apologise to a Liberal staffer for "sniffing her chair" in 2005. Earlier in 2008 he was reprimanded for a bra-snapping incident with a Labor staffer - both antics widely considered to have cost him the Liberal Party leadership in August 2008.