Scott Brown chose club over country on Friday, announcing his retirement from international football so he could prolong his career with Scottish champions Celtic.

The 31-year-old midfielder -- who won his 50th and final cap against Denmark in March -- said it had been a tough decision but after much thought he had decided to call it a day and had informed national coach Gordon Strachan.

"Gordon has been one of the most influential people in my career and I did not want to let him or my country down, but over the summer I had a lot of thinking to do," said Brown, who has captained the national side 21 times after Strachan named him skipper in 2013.

"It's no secret that I've suffered some injuries in my career and once you get over 30 you have to protect your body more, in any case.

"I'm not the type of player who can coast half-heartedly through a game - I give 100 per cent every time.

"Given the importance of this campaign for Scotland, and the challenges ahead at Celtic, I simply felt that I could not keep up both commitments without either my performances or recovery time suffering," added Brown, who has been with Celtic since joining from Hibernian nine years ago.

Brown, who made his debut in 2005, said he regretted never reaching a major finals but believed there is enough talent in the national squad to set that wrong right beginning with the 2018 World Cup finals in Russia.

"I genuinely think we showed in the last campaign that we are good enough to compete with Germany, the world champions, and other nations who qualified ahead of us," said Brown.

Strachan, whose side open their World Cup qualifying campaign against Malta next month, praised Brown for his influence on and off the pitch.

"Scott is one of the most wholehearted players I've encountered and somebody who puts the team ahead of himself," said Strachan.

"He is not the type to play within himself, either, and I understand and respect the decision he has taken.

"I have huge admiration for a player as selfless as he has been to sacrifice family time and recovery time to help his country.

"We'll miss him as a person, too, because his influence and popularity around the squad was integral to all that we did as a group."