Tim Paine quits as Australia captain after sending explicit messages to a female colleague

Tim Paine has resigned as Australia's Test captain on the eve of the Ashes after an investigation by Cricket Australia into explicit messages he sent to a colleague.

Paine told a press conference in Hobart on Thursday that he would give up the captaincy after admitting a text exchange with a female co-worker at Cricket Tasmania in 2017.

The 36-year-old, who has captained Australia's Test team since Steve Smith quit over the ball-tampering scandal in 2018, insisted he had not breached Cricket Australia's conduct rules over the messages but said the decision was right for the reputation of the sport.

Watch: Australian Test captain Paine quits over sexting scandal

"Nearly four years ago, I was involved in a text exchange with a then-colleague," Paine told reporters in Hobart. "At the time, the exchange was the subject of a thorough CA Integrity Unit investigation, throughout which I fully participated in and openly participated in.

"That investigation and a Cricket Tasmania HR investigation at the same time found that there had been no breach of the Cricket Australia Code of Conduct.

"Although exonerated, I deeply regretted this incident at the time, and still do today. I spoke to my wife and family at the time and am enormously grateful for their forgiveness and support.

He added: "We thought this incident was behind us and that I could focus entirely on the team, as I have done for the last three or four years."

"However, I recently became aware that this private text exchange was going to become public. On reflection, my actions in 2017 do not meet the standard of an Australian cricket captain, or the wider community.

"I'm deeply sorry for the hurt and pain that I have caused to my wife, my family, and to the other party. I'm sorry for any damage that this does to the reputation of our sport."

Paine is said to have exchanged "increasingly flirtatious" messages with the woman around the time of the first Ashes Test in Brisbane in November 2017, culminating in him texting her an "explicit picture", according to the Herald Sun newspaper.

The woman later told cricket authorities in June 2018 that she was offended by "Mr Paine’s sexually explicit, unwelcome and unsolicited photograph...in addition to the graphic sexual comments".

Paine had faced a race to be fit for this year's first Ashes Test in Brisbane on December 8 but insisted on Thursday that he remained available for selection, though his role as captain had become untenable.

"I believe that it is the right decision for me to stand down as captain, effective immediately," Paine said. "I do not want this to become an unwelcome disruption to the team ahead of what is a huge Ashes series."

"I have loved my role as captain of the Australian cricket team," he said. "It's been the greatest privilege of my sporting life to lead the Australian men's test team. I'm grateful for the support of my team-mates and proud of what we've been able to achieve together.

"To them, I ask for their understanding and forgiveness. To Australian cricket fans I'm deeply sorry that my past behaviour has impacted our game on the eve of the Ashes. For the disappointment I have caused to fans and the entire cricket community, I apologise."

Paine's wife Bonnie, who he married in 2016, was reportedly aware of the messages but chose to stick by him.

The board accepted Paine's resignation and has said that process of identifying and appointing a new Test captain will be accelerated.

In a statement, Cricket Australia chairman Richard Freudenstein said: "The Board has accepted Tim's resignation and will now work through a process with the National Selection Panel of identifying and appointing a new captain.

"While the Board acknowledges an investigation cleared Tim of any breach of the code of conduct regarding this matter some years ago, we respect his decision. CA does not condone this type of language or behaviour.

"Despite the mistake he made, Tim has been an exceptional leader since his appointment and the Board thanks him for his distinguished service."

Cricket Tasmania chairman Andrew Gaggin has released a statement saying: "As soon as Cricket Tasmania was made aware, it undertook an investigation that determined the interaction was consensual, private, occurred on the one occasion only, was between mature adults and was not repeated."

Fast bowler Pat Cummins is Australia's current vice-captain and had been tipped to become captain once Paine retired. Alex Carey and Josh Inglis are the favourites to replace Paine as wicketkeeper.