London - On the day that he unveiled Andy Farrell as one of his assistant coaches, Warren Gatland conceded that the credibility of the Lions was at stake if they returned from Australia without a series victory.

Gatland also admitted it had been the hardest decision of his life to break the news to long-time friend and coaching ally, Shaun Edwards, that he would be taking Edwards's former Wigan team-mate, Farrell, rather than him as one of the three assistant coaches.

Farrell was paraded in the opulent surroundings of Hopetoun House just outside Edinburgh, and hailed as one of those hired to not only help beat the Wallabies but also to save the Lions brand in the process. There was no attempt to downplay the fact that another series defeat, which would be the Lions' fourth since victory in South Africa 15 years ago, would threaten the credibility of the iconic touring side.

''All the discussion after the 2005 trip to New Zealand was of wondering if the Lions were dead and would they be scrapped,'' Gatland said.

That prospect was also acknowledged by assistant coach Rob Howley, who was involved in the 2009 tour to South Africa. ''Those questions will continue to be asked until a Lions series is won,'' he said.

Gatland immediately upped the ante for the trip by describing Australia as ''the easiest place to tour''. He said: ''If you'd said to me, out of the three southern hemisphere teams, pick your choice of where you'd like to go, I would've said Australia probably.''

Gatland was wary of the Wallabies using off-field diversionary tactics as a means of unsettling visiting teams. ''They will do whatever it takes to get a result,'' said the Lions head coach, rather well-equipped himself in the sledging stakes.

Farrell spoke of travelling with Wigan as an 18-year-old to take on the Brisbane Broncos in rugby league's World Club Challenge in 1994. ''We weren't given a cat in hell's chance of going over there in their backyard, and there were 62 000 there that day, a full house and we turned them over,'' he said.

''It was a big shock for everyone. That's what stayed with me. Australia is a real sport-loving nation. There will be a lot of old tricks of the trade coming our way on a six-week tour. They'll try to get stuck into us, try to ruffle our feathers.

''But you look at the players that the British and Irish Lions are going to take over, and you can't not be full of confidence.''

Farrell is aware of the his privileged position, barely a year since he was drafted from Saracens by England's Stuart Lancaster to take on his first coaching role in international rugby. He fleetingly backtracked on that decision when opting to stay with Saracens after the previous year's Six Nations championship, only to change his mind. That his rise has been swift will not have been lost on Edwards, who has many more years of experience to offer, a Lions tour three years ago included.

''You couldn't get any more similar than me and Shaun, from the same background,'' Farrell said. ''He was the first to text me after we beat the All Blacks even though Wales had just lost to Australia. We're good friends. We haven't spoken [about the Lions] but we will.

''It's been a hell of a year so far. It's unbelievable. I feel very fortunate to have an opportunity like this early in a coaching career. It's something I'm very proud of as well. It's always been a dream to be associated in some way with a Lions tour.''

The Lions coaches went through the process of choosing a putative 36-man squad on Tuesday night, excluding those who were injured. The third assistant coach, Graham Rowntree, revealed that it had taken them an hour to decide on the composition of the back row alone.

Hopetoun House was once the ancestral home of the governor-general of Australia. That post has become a relic of the past. Every effort was being made yesterday to ensure the Lions did not follow suit.