Nobody knows when Arsene Wenger's time as Arsenal boss will come to an end, says Ivan Gazidis

Chief executive Ivan Gazidis says Arsenal are preparing for the "long-term" under Arsene Wenger despite the Frenchman entering the final year of his contract with the club.

The 66-year-old - Arsenal's longest serving manager - brings up 20 years in charge of the Gunners this October, but has so far given no indication whether he intends to remain in charge beyond next season.

Arsenal have won nine major trophies under Wenger

Despite six FA Cup wins and Champions League qualification during every year of his tenure, Wenger's relationship with a section of the club's supporters has become strained over Arsenal's failure to challenge for the Premier League in recent seasons.

They last won the title in 2004 and have failed to reach the quarter-finals of the Champions League since 2010, but Gazidis says the board and the manager are convinced the club is heading in the right direction.

"He [Wenger] is in his mid-sixties, it's natural to think about when his time here might come to an end, but the truth is nobody knows," Gazidis told the Telegraph.

Arsenal supporters staged protests against Wenger and the board during Norwich clash

"He is in fantastic shape. He is deeply engaged and excited. One of the biggest challenges we will face is the transition, whenever it happens, but that is not something we are going to be facing imminently.

"Obviously, he is going to be managing us next year and we are planning and making many decisions for the long term.

An Arsenal fan held up a sign in a show of support for Wenger in the game with Norwich

"The reality is we wouldn't leave things until the last minute. I'm comfortable both that if Arsene is going to extend we will know that and if, whenever that is, he is going to come to an end, that he will give us the time that we need to prepare for that transition.

"The relationship with Arsene is very deep. It will be done behind closed doors and we will have our transition plans well worked out.

Gazidis says Arsenal's relationship with Wenger runs 'very deep'

"He has always put the long-term health of the club first. He wants to hand over a football club, whenever that it is, that is in great shape. He views that as a massively important part of his legacy.

"But we are just not in that mode. I know Arsene wouldn't stay on if he thought the club wasn't heading in a good direction and thought he wouldn't be able to deliver what the fans want."

Arsenal finished second last season as Leicester claimed the first top-flight title in the club's 132- year history.

Arsenal have strengthened midfield with signing of Granit Xhaka

Injuries were once again a thorn in Arsenal's side last term and the club have begun the process of adding quality to their squad with the signing of highly-rated Swiss midfielder Granit Xhaka in a deal thought to be worth in the region of £30m.

"We have to be disappointed, certainly not satisfied, to end up second," Gazidis said of last season's campaign.

Granit Xhaka has described his move to the Arsenal as a dream Granit Xhaka has described his move to the Arsenal as a dream

"We wanted more than that and I think that there were chances during the season. We are taking a long, hard, realistic look at why we fell short of our ambitions. You can't say second place is a disaster, but it's not what we are about.

He added: "We are in a position that we were not in four or five years ago where we don't have to sell our best players. We can go and sign world-class players if and when the manager identifies them."