“I couldn’t carry things so I used to wear a rucksack everywhere - even in the house. Crutch down to the kitchen, fill the rucksack, crutch back upstairs. It’s like going camping in your own house. I’m sure I could have put my foot down. But if I did so I was risking everything.”

After the surgery came the pain, excruciating in the early days. He kept telling himself that some people had to deal with this every day of their lives. All he had to do was survive six weeks. But there were times, in the middle of the night when he would lie awake aching for the loo and wondering what the least worst option would be.

“I can’t wake my girlfriend up at 4am and say ‘Can you empty my wee?’ She would have done but she has work the next day. You find yourself doing silly things. Trying to hold it for the morning. Wondering if I can I wee in the pot and put it on the side. Will it spill? I can’t carry anything whilst I crutch. Can I hold it with my teeth? Trying to plot how to get to the toilet in the middle of the night.”

He found himself looking forward to milestones much simpler than being able to lace up his boots and go outside and volley a football. “It just went to an appreciation of, ‘I can’t wait until I can walk’. Or, ‘I can’t wait until I can sit on the toilet properly’. I wasn’t allowed to bend my leg so I when I was on the toilet I had to have a little footstool to rest my foot on. I had one as a kid to reach the toilet.”

At the end of July, as he approached his holiday in Greece and then Los Angeles, there were concerns that the angle of bend his new knee could achieve was not on schedule. By then he was already running on a machine and doing some squatting but he needed that flexion to do all the things that once came as second nature – jumping, twisting, falling over and getting back up. That was when it was decided that his surgeon, Andy Williams, would put him under again and manipulate the leg. He plays the video on his phone and turns the volume up.

Oxlade-Chamberlain’s knee injuries explained

His leg is being pushed back beyond its usual angle of bend. “The scars are tearing,” he says. “There you see it ping back to where it wants to go to. Even after I had this I was still way off it.” What will truly bring it back will be the times in training or games when he falls on it and the knee is forced to give way again. It will be sweet agony for a couple of seconds but it will do the knee good. He imagines that moment: “Have that! BOSH! A minute of pain and then I run it off.” It will take around two years to regain the full range of motion.

Then there was the World Cup. He watched it at home and enjoyed it. He was persuaded by mates to watch the group game against Belgium at Shoreditch Boxpark. It was a source of fascination to see the support so enraptured. He watched groups of friends meeting after work, rushing in time for kick-off, and the shared anxiety of being a fan. “I said to my friends, ‘Is this what it’s like when I’m playing and you lot watch the game down the pub?’ They were like, ‘Yeah, Chambo, this is why it’s so weird for us. Because we know you’re just an idiot and yet we sit with people at the pub worshipping you’.”

“I loved every minute of it as a supporter. I felt that buzz that we all do as England fans. Plus of course, the lads, as well as the staff, are my mates. They are people who I’ve grown very close to, and who I want to be successful. As players, we saw a lot in Gareth Southgate when he took over that perhaps took longer for everyone else to get about him. I love that he proved so many people wrong.

“As a professional, as someone who would in all likelihood been playing some part, it was surreal. It’s hard to explain the feeling without it sounding selfish or maybe even unpatriotic. But it isn’t that. It’s human nature I suppose – the ‘it-could-have-been-me-feeling’.”

He was not a first XI pick when he missed out on Euro 2012 and the 2014 World Cup. This time, his performances for Liverpool had meant that he started both the crucial March friendlies against Holland and Italy. He believed he could have started for Southgate had he been fit, and stayed in the team.

“That is where you have to fight the injury in ways that go beyond just the hard work and the boredom of rehab. You are missing out on great experiences and great moments – and these moments are taking place in front of your eyes. I suppose I did feel an element of grief at what the injury had taken away from me and that was worse at certain periods – especially the World Cup. A month earlier I’d had to watch a Champions League final I would have played some part in and now I am watching England put in their best World Cup since 1990.

“The further they went, the more I had to contend with that mixture of emotions. What do I feel in my bones? I loved seeing the boys play so well. I got carried away like everyone else. We were singing in the living room like I bet a lot of English families were. In the knockout stages I had proper goose-bumps before each game. I wanted them to get to the final and win it, although I know that would have come with something else too – a kind of mourning that I had missed out. I would have backed myself to deal with it positively though. I’m that kind of person.”

He watched the first game of Liverpool’s season in an Irish bar on Sunset Boulevard at lunchtime, empty apart from him and his friends and a couple of fans who did not realise until the end of the game who it was under the baseball cap. As his rehabilitation continued he was conscious of managing expectations. A video taken of him on the indoor pitch at Melwood pinging a ball sweetly on the half-volley with his left foot was shot on Oct 21. He did not post it on Instagram until Nov 16, when he felt he was closer to training with the first team.

He had Christmas Day at home uninterrupted by training for the first time since he turned professional. The club had given him New Year off, which he spent with Perrie in Dubai. He was back there later that month with the first team and by Feb 12, when the squad went away again to Marbella, he joined in first team training for the first time. A little irritation to his knee meant that he was limited to rondos, the keep-ball exercises. It was supposed to be a private session but someone at the hotel caught the session on their phone and secretly he did not mind. He had looked sharp.

There are no half-measures when it comes to a player returning to full-contact first team training. A judgment has to be made as to whether he can either live with the intensity or not. Back at Melwood the week after Marbella he went in for the first time. He got the impression that a couple of his team-mates might be standing off him, and his reaction was to be as physical with them as he would be pre-injury. “After that they feel it’s fine to do the same to me. Because I am not pussyfooting around, then they don’t.”

“Hendo [Jordan Henderson] crunched me first time back. He didn’t mean to but he gave me a good little tackle and clattered into me. I stumbled and then reacted, chasing the ball.” He felt fine. There was another convention to be observed too. He had not yet played against the summer’s new arrivals, and in his mind was the old anxiety of re-establishing himself among the pack.

“I wanted to look better than Naby Keita and Fabinho and [Xherdan] Shaqiri because they hadn’t seen me. In my head I didn’t care I had been out 11 months, there was the pressure of ‘I need to show them’. As soon as I was out on the pitch, when Trent or the full-back would get the ball I was making the runs I was making last year. Suddenly, I was in behind Matip and thinking, ‘I shouldn’t be here’. But I was also thinking, ‘I’ve still got it, boys’.”