Steve Smith and David Warner have been banned by Cricket Australia for a year for their involvement in the Cape Town ball tampering scandal, with the revelation that sandpaper was used in an attempt to rough up the ball.

Cameron Bancroft, who had claimed he used sticky yellow tape, was banned for nine months.

Warner was found to have been responsible for the "development of a plan to attempt to artificially alter the condition of the ball", and "instruction to a junior player to carry out a plan".

The former vice-captain was also charged with providing advice to a junior player on how to tamper with the ball "including demonstrating how it could be done".

Warner also misled the Newlands match officials by concealing his knowledge of and involvement in the plan and did not voluntarily report his involvement.

Bancroft charged, Smith admits ball tampering ploy

Steve Smith's ban was based on him knowing of the plan but failing to take steps to prevent it.

Further, CA's investigation found that it was Smith who directed "that evidence of attempted tampering be concealed on the field of play". In other words, Smith told Bancroft to hide the sandpaper in his trousers.

Smith was also found to have "misled match officials and others regarding Bancroft's attempts to artificially alter the condition of the ball" and "misleading public comments regarding the nature, extent and participants of the plan".

Bancroft, the most junior member of the playing XI in Cape Town, was charged based on being party to the plan to tamper with the ball, carrying out Warner's instructions, following Smith's direction to conceal the evidence and his own lies to mislead match officials and the public.

Warner will never again be considered for any leadership position, while Smith and Bancroft must wait 12 months after serving their ban before they can be considered for a leadership role.

Any appointment would be conditional on form, stature in the playing group and, perhaps most importantly, acceptance by fans and the public. As confirmed by CA's Board yesterday, Tim Paine is the captain of the Test team.

The offending trio are banned from all international cricket and domestic cricket in Australia, but can still play and are encouraged to return to club level to help re-connect with the cricket community.

However, in the wake of being suspended, Smith and Warner have both had their Indian Premier League contracts torn up. The pair were each on $2.4 million contracts before the IPL banned them from the 2018 season.

A key finding from the investigation was that sandpaper was used by Bancroft to rough up the ball, which goes against what the Test rookie said after play on Saturday when he and Smith fronted the press at Newlands.

Bancroft, Smith reveal ball tampering plan

The CA Board, comprising of Chairman David Peever, Earl Eddings, Dr Bob Every, John Harnden, Tony Harrison, Jacquie Hey and Michelle Tredenick, as well as former Test players Mark Taylor and Michael Kasporwicz, convened for two-and-a-half hours on Wednesday to determine the sanctions imposed on the guilty trio.

In the early hours of Wednesday (AEDT), CA chief executive James Sutherland revealed that Smith, Warner and Bancroft were the only members of Australia's touring party – players or support staff – who had any knowledge of the plan to deliberately alter the condition of the ball.

The three sanctioned players were ordered home, with Matthew Renshaw, Joe Burns and Glenn Maxwell called up as their replacements.

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Smith, Warner and Bancroft have up to seven days to appeal CA's sanctions if they wish.

The incident that led to the suspensions took place during South Africa's innings on Saturday afternoon when Bancroft was seen on television holding a foreign object while rubbing the ball, before hiding the object in his pocket, then inside his trousers.

As soon as the incident was shown on the big screen, the player was questioned in the presence of his captain by the two on-field umpires, Richard Illingworth and Nigel Llong, who, along with third umpire Ian Gould and fourth umpire Allahudien Palekar, later charged Bancroft.

The umpires inspected the ball at that time and elected not to replace the ball and award a five-run penalty as they could not see any marks on the ball that suggested that its condition had been changed as a direct result of Bancroft's actions. The umpires, though, agreed that Bancroft's actions were likely to alter the condition of the ball and he was therefore charged.

The plan to alter the condition of the ball had been made at the lunch break on day three without the consent of the coaching staff, according to Smith.

Bancroft was tasked with using the sandpaper by Warner and was caught doing so.

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Match referee Andy Pycroft said: "To carry a foreign object on to the field of play with the intention of changing the condition of the ball to gain an unfair advantage over your opponent is against not only the Laws, but the Spirit of the game as well.

"That said, I acknowledge that Cameron has accepted responsibility for his actions by pleading guilty to the charge and apologising publicly. As a young player starting out in international cricket, I hope the lessons learned from this episode will strongly influence the way he plays the game during the rest of his career."

Smith had not missed a Test since March 2013 in India, a streak of 59 matches in which he scored 23 Test centuries, was handed the Test captaincy and ascended to the top of the Test batting rankings.

He fronted the media on Saturday night and confessed his regret and part in the wrongdoing.

"Obviously, today was a big mistake on my behalf and on the leadership group's behalf as well," he said. "But I take responsibility as the captain, I need to take control of the ship, but this is certainly something I'm not proud of and something that I hope I can learn from and come back strong from.

"I am embarrassed to be sitting here talking about this."

Qantas tour of South Africa

South Africa squad: Faf du Plessis (c), Hashim Amla, Temba Bavuma, Theunis de Bruyn, Dean Elgar, Heinrich Klaasen, Quinton de Kock, Keshav Maharaj, Aiden Markram, Morne Morkel, Chris Morris, Wiaan Mulder, Lungi Ngidi, Duanne Olivier, Vernon Philander, Kagiso Rabada, AB de Villiers.

Australia squad: Joe Burns, Pat Cummins, Peter Handscomb, Josh Hazlewood, Jon Holland, Usman Khawaja, Nathan Lyon, Mitchell Marsh, Shaun Marsh, Glenn Maxwell, Tim Paine, Matt Renshaw, Jhye Richardson, Chadd Sayers, Mitchell Starc.

Warm-up match: Australia beat South Africa A by five wickets. Report, highlights

First Test Australia won by 118 runs. Scorecard

Second Test South Africa won by six wickets. Scorecard

Third Test South Africa won by 322 runs. Scorecard

Fourth Test Wanderers, Johannesburg, March 30-April 3. Live coverage