Kieran Tierney has become the most expensive player in the history of Scottish football.

The Celtic left-back completed an English transfer deadline day move to Arsenal for a fee of around £25m.

Tierney, 22, signed a long-term deal with the Premier League giants after travelling to London on Wednesday.

Celtic said that they had not wanted to sell the Scotland international but that Tierney had wanted to move and the club had received a significant return for a player they developed themselves.

"We did all we could to keep Kieran at Celtic," a club spokesperson said. "While the club did not need or wish to sell Kieran, this was an opportunity which Kieran very much wished to pursue and with the club having received a significant offer, we have agreed to the transfer."

Celtic boss Neil Lennon said: "This is an opportunity Kieran wanted to take and while we will be sad to see him leave the club, we wish Kieran all the very best for the future.

"Although he is still a young guy, Kieran has given the club so much. He's a great lad and I've really enjoyed working with him. I'm sure he will continue to progress and develop and make a big impact in the English Premiership.

"It has obviously been a long process, but now it has been finalised we can now look ahead and concentrate on continuing to build our own squad and meet the many challenges ahead, domestically and in Europe.

Arsenal completed the move just ahead of the English transfer deadline and manager Unai Emery said he was signing a player who could still develop his game.

"We're delighted Kieran is joining us," he said. "He's a very talented player who will continue to improve.

"He increases our options defensively and I look forward to him joining our group."

The three-time PFA Scotland Young Player of the Year joined Celtic at at the age of just seven and rose through the youth ranks to become a vital player at club and international level for Scotland.

Injury problems meant he didn't feature in any of Celtic's five Champions League qualifying games over the last month.