Director of cricket Rob Key said he is "gutted, disappointed and sorry" for England being at "20% capacity" in their awful Ashes campaign.

England once again lost the first three Tests in Australia to extend their winless run in this country to 18 matches and remain without a series victory here since 2010-11. In what was billed as a supreme opportunity to win back the urn from a weakened Australia team, England lost the series in 11 days of cricket and will be battling against a 5-0 clean sweep in the remaining Tests in Melbourne and Sydney.

"I don't feel like we've put anything like the best account of ourselves out here," Key told BBC Sport. "The most frustrating, disappointing thing is that we're so much better than what we've shown. We've got some brilliant players that haven't been anywhere near their full capacity, which is what you're trying to do in these jobs. I don't feel like we've always given them the best chance to do that."

In a wide-ranging interview, former Kent and England batter Key said:

• He wants to stay in his job but says he may not get the chance
• Captain Ben Stokes and head coach Brendon McCullum have his backing
• He apologises to England supporters for the outcome of the tour
• England will investigate reports of excessive drinking on the players' holiday in Noosa
• The tourists did not have the correct preparation for this series
• England players sometimes made "stupid decisions" on the field

Key took over as director of cricket in 2022, in the aftermath of a 4-0 defeat on the previous tour of Australia. He appointed Stokes and McCullum as captain and coach respectively of the Test side. Matthew Mott took charge of the white-ball teams and, although the Australian led England to victory in the 2022 T20 World Cup, he was sacked in 2024.

New Zealander McCullum is now in control of all England teams, and his future, along with that of Key, is complicated by a T20 World Cup in India and Sri Lanka early next year. Stokes and McCullum have said they want to stay in their roles, but pressure on England's leaders will increase if the tourists suffer the indignity of a 5-0 clean sweep in Australia.

Key stated, "Ben's done an excellent job as captain," said Key, who played 15 Tests for England between 2002 and 2005. "I see a dressing room that still follows the captain, still follows the coach, which is a credit to them really, because this is not easy at all. The England and Wales Cricket Board will have a decision about whether it's trying to rip it all up and start again or whether it's about evolution rather than complete revolution."

Three previous England teams have been beaten 5-0 in Australia. The fourth Test, in front of an expected first-day crowd of 100,000 at the Melbourne Cricket Ground, begins on Boxing Day. Thousands of England supporters will travel to Australia for the Christmas period.

"I'm sorry to everyone that supports and has been through this journey with us all the way," said Key. "I haven't got the biggest vocabulary. I struggle to find anything to say other than I'm completely gutted for what we've done. It's so important we go out there to put on a proper show and be as successful as we possibly can be for the people that have come. You see people that have spent a huge amount of money, a huge amount of their life savings stuff to come and watch us play and watch us be successful, and you're just absolutely gutted when you don't."

England's preparation for this series was questioned by several former players before the first Test. The visitors played one warm-up game against England Lions at Lilac Hill, a club ground with vastly different conditions to Perth Stadium, the venue for the series opener. England's situation was complicated by a white-ball tour of New Zealand in October, a series Key said he did not want to "write off". Although the England management defended their preparation, McCullum has since admitted it was not correct.

The ECB have also opened negotiations with Cricket Australia about guaranteeing minimum standards for preparation in future Ashes series. Key said England asked to warm up at Perth's historic Waca ground, only to be told it was unavailable. "In hindsight, it's very hard to argue that it's been right," said Key. "The answer isn't yes, I would have gone and played four games against state teams - I don't think that is possible in this day and age - but we still had to be better with what we did."

Stokes and McCullum revitalised England's Test cricket when they took over. England's form has stagnated in the past 18 months, although there was still genuine optimism over the prospect of a competitive series in Australia. Those hopes were raised by a number of injuries to the home side, including captain Pat Cummins, fellow fast bowler Josh Hazlewood, spinner Nathan Lyon and batter Steve Smith. Instead, Australia have retained the Ashes they have held since 2017-18.

"Sometimes we make stupid decisions as players out there in the middle," said Key. "We've got to try and equip them to be able to make better decisions when the pressure's really on." Key said there is room in the dressing room for players to challenge the directions given by Stokes and McCullum, and England are not wedded to a style of play.

"One of the problems with the Bazball narrative is me and Brendon McCullum, we've never spoken about 'we've got to score quick; this pitch is five and over'. What we're trying to do is create an environment where people can maximise their potential and then you then pick the style that you want. I'm not in the dressing room all the time to know exactly what happens, but there's been many occasions where you've seen players challenge, where the players have driven it."