Australia have responded to the chronic form and crumbling discipline that has made a laughing stock of their Ashes preparations by sacking their South African coach little more than a fortnight before the first Test at Trent Bridge and replacing him with Darren Lehmann.

A much-loved character from Yorkshire to the Yarra, and an old school Aussie, Lehmann immediately said he plans to involve a number of "past legends", starting with his former Victoria state team-mate Shane Warne, in an effort to rebuild the credibility of the Australia team.

Mickey Arthur was informed at the team's Bristol hotel over the weekend that he would pay the price for the combination of on- and off-field embarrassment that began on a recent Test tour of India, where Australia were thrashed 4-0 and he was widely mocked for setting various pieces of homework that four of his players failed to take seriously.

The grief continued this month during the Champions Trophy, where they failed to win a match and were further disgraced by David Warner's knockabout in the Walkabout hours after their defeat by England at Edgbaston.

Lehmann, who describes himself on Twitter as "a very old, bald cricketer who enjoys having a beer with the general public", was already handily placed to succeed Arthur, having been assistant to Rod Marsh with the Australia A team who have been on tour in Scotland, Ireland and England for the past three weeks. He has been widely praised for his work as coach of Queensland and now the 43-year-old, who played 27 Tests and 117 one-day internationals for Australia, - and hit the winning runs in the 1999 World Cup final against Pakistan at Lord's - has signed a two-year contract that will start with back-to-back Ashes series.

Lehmann said he would be setting out the standards demanded of his players at a meeting in Bristol on Monday night. He did not rule out doing so over a beer, although presumably not at the city's Walkabout bar.

"There will not be any ongoing problems," he said with a slightly steely smile, offering the ultimate hostage to fortune for the remainder of the trip. "We will get everything right on and off the field. It is important to talk about the game – whether it be with a beer or a Diet Coke, I don't care. It's about learning the game and improving our skills on and off the field. This journey over the next two months with the Ashes, we will learn about ourselves as cricketers and people."

New Australia coach Darren Lehmann put on a positive face as he was unveiled at a press conference in Bristol on Monday. Photograph: Geoff Caddick/AFP/Getty Images

Asked directly about Warne, with whom the South Australian shared a dressing room and numerous fag breaks in four seasons with Victoria from 1990-93, Lehmann said: "We would love him in the room. The past legends is what we are about. Having guys involved in our current structure and having some sort of input. You don't have a guy take 700 Test wickets and not use him if he is around the place. He is always welcome as are anyone representing Australia in our dressing room. I will be after the past players to use their knowledge and guidance along the way. If he is around – and I know he is commentating with Sky all the time – then we will certainly use him."

On the latest trying day for Australian cricket James Sutherland, the chief executive of Cricket Australia, and Pat Howard, the former Wallabies fly-half who is now the general manager for team performance, were forced to defend their positions and the timing of their surprise announcement on Lehmann.

Explaining the decision to sack Arthur, which was confirmed early on Monday, Sutherland said: "Recent on-field results have been too inconsistent. Discipline, consistency of behaviour and accountability for performance are all key ingredients that need to improve. And we see that the head coach is ultimately responsible for that."

Michael Clarke confirmed that he had been stunned when told of the decision on Saturday night. "No doubt it is a massive shock to all [of the players]," said the captain, who has also stood down as a selector "to spend more time focusing with the team". Clarke added: "I think we understand, though, [that] we have not performed as well as we would have liked. Our performances in India were unacceptable. We have not started this tour well. We expect higher of ourselves. We need to be the ones to turn that around."

Clarke was non-committal about the effect on Australia's Ashes prospects of the change in management, perhaps out of loyalty to Arthur.Lehmann, who offered to give up his Test place to Clarke after the youngster had scored a century on debut in Bangalore in 2004, was more bullish. Asked whether Australia could emerge from this shambles to regain the Ashes, he said: "Yes, definitely. We are going to play an aggressive brand of cricket that entertains people and fans and gets the job done on and off the field. I am excited by the challenge. I am looking forward to working with Michael closely and the other team members and look forward to them having success throughout this tour."

Later, asked about his own job security given the ruthless treatment of Arthur, Lehmann joked: "If Michael gets some runs I will be OK. But if we don't win I will go – that's what happens in professional sport, it's what happens in this country with [Premier League] teams, isn't it? You are head coach. You have to get results. If you don't, you see what happens."

Lehmann will take charge of the team for the first time in a four-day match against Somerset that starts at Taunton on Wednesday – one of only two games before the first Test. Clarke is expected to make his first appearance of the tour at Taunton after missing the Champions Trophy because of a back problem.