Smith was appointed England's new attack coach on Monday and the Exiles have decided to promote Booth, his number two at the Madejski Stadium, to plug the gap.

Mike Catt will take on greater tracksuit responsibilities as part of an expanded player-coach role.

Irish chairman Andrew Coppel said: "It was always our preference to promote internally provided we had the right calibre of staff.

"I'm delighted that Toby has agreed to become head coach, supported by Mike.

"These appointments also provide vital continuity as we seek to build on the momentum of the last two years."

Booth's stock is rising following three years as Irish's forwards coach and the 39-year-old is viewed as innovator with a bright future.

He has established the Exiles' line-out as one of the most formidable in Europe and was part of the management team that led the England Saxons to Churchill Cup glory last month.

Irish have been one of the most entertaining sides to watch in the Guinness Premiership in recent times and Booth vowed to persevere with the swashbuckling style.

Booth said: "We plan to operate an integrated approach among the coaches with each supporting and challenging the other.

"The positive approach to playing the game that has been the hallmark of London Irish in recent seasons will continue."

Catt, who took on greater responsibility with the backs last season, insisted he is relishing his new duties.

Catt said: "There comes a time in every player's career where he has to look to the future.

"For me moving into full-time coaching is a natural progression and I'm pleased to have the opportunity of doing so."