I had lost mental edge: Cook

England opener Alastair Cook says he decided to call it quits since he had lost the mental edge with which he managed all his tasks with ease.

The fifth and final Test begins at the Oval on Friday, and with the hosts already 3-1 up, it will be the last international match of Cook's 12-year-long career.

"I've always had that mental edge, I have always been mentally incredibly tough and had that edge to everything I have done but that edge had kind of gone. The thing I had found easy before was not quite there and to me that was the biggest thing, Cook said.

He said he would have kept the decision to himself if the series had not been decided in Southampton.

"It's been a bit surreal. One of my friends rang me to check I was still alive because everyone was talking as if I'd died. It is nice when you hear so many nice words said about you. For example, someone stopped me when I was driving in and made me wind down the window and said thank you very much.' That was a nice moment. Hopefully this week I can score some runs and then go, Cook said.

Asked about the decision to call time on his long career, Cook replied, It's hard to put into words but there have been signs in my mind over the last six months. I told Joe Root before the game (in Southampton) and then Trevor Bayliss during the game. In this day and age it's very difficult to keep anything quiet. If it were 2-2 I'd have kept my mouth shut."
"When you get asked questions (from the media) it's hard to constantly lie. I've been pretty good at it! But there's certain stuff when you're asked questions you know you're not being true to yourself. There might be a bit of fuss about it and if it were 2-2 Id have kept my mouth shut."
"You can't really look past those two away series where I was man of the series and we won in Australia and India. That was the best I could play and probably in my career as a whole I can look back and say I probably became the best player I could become. That actually means quite a lot to me. Yes, I've never been the most talented cricketer and I can't pretend I was but I definitely think I got everything out of my ability."
"Of course there are decisions in hindsight that you question. Clearly the KP affair was a tough year, there's no doubt about that. The fall-out of that wasn't great for English cricket and wasn't great for me. I was involved in that decision without being the bloke who actually made the final decision. The fall-out of that decision and the effect it had for 12 months was immense."