When Andy Murray was watching Great Britain playing in last year's Davis Cup, he knew immediately he had made a mistake.

At the time he said he was "not sure he deserves to play" in Leon Smith's team when other British players were enjoying fine form.

This year, there was no way he was just going to watch on TV - even if he does not end up playing.

Murray is in the five-man team alongside Cameron Norrie, Dan Evans, Joe Salisbury and Neal Skupski for Great Britain's three group-stage matches in Glasgow this week.

"I regretted not being involved last year," Murray, 35, told a news conference before Great Britain open their campaign against the United States on Wednesday.

"I was tired and I wasn't sure if it was something I necessarily still wanted to be involved with because all of these guys deserve to compete in the team and whether it was necessary for me to be there.

"As soon as I turned the matches on [last year] to start watching I was like 'What am I doing? Like, it's a mistake'. I wanted to be there and be there for the team and try and help.

"Obviously, I spoke to Leon about that and if I was in a position to be selected I wanted to be part of the team again."

Murray, whose career was nearly ended when he needed a hip resurfacing operation in 2019, says he does not necessarily expect to play although is feeling physically "really good".

With British number one Norrie, number two Evans and Murray all ranked inside the world's top 50 singles players, and Salisbury and Skuski the world's top and third-ranked doubles players, the consensus among the team is that it is the best they have ever had in terms of depth.

"All of us are playing close to some of our best tennis and obviously we're all in-form players," said Norrie, who is ranked eighth in the world and reached the fourth round of the US Open this month.

Salisbury and Skupski arrive in Glasgow a few days after meeting in the US Open men's doubles final, where Salisbury retained the title alongside his American partner Rajeev Ram.

Whether in singles or doubles, if he is called upon for the ties against the US, Kazakhstan and the Netherlands, Murray is ready to perform.

"It's a slightly different situation than five or 10 years ago when I was playing Davis Cup but the job remains the same," said the former world number one, who contributed 11 of the 12 points Great Britain needed to win the Davis Cup seven years ago.

"I don't expect to play - everyone that is sitting up here deserves the opportunity to compete and if I don't play at all then I trust the players who go out there will go and do a great job and win matches for us.

"All of us want the same thing - the goal is the same for everyone. Just try and be the best team-mate that you can and support everyone. If you get called upon go out there and give it your best and try and get some wins."

Smith says it is a "huge privilege" to have Murray in the team.

"With Andy he's got not just experience of Davis Cup but everything he has achieved in the game, the way he is on and off the court, he's a good friend to all of us as well, to spend time with him is good fun, we see that side a lot," he said.

"He brings a lot. He's someone all of these guys will have watched for years growing up and looking up as a role model, it's still the case, he's given an awful lot to British tennis and world tennis - and he continues to do so."