Northampton Saints scrum-half Alex Mitchell says he has renewed "fire in the belly" and wants to lead club and country to new heights after recovering from a neck injury.

Mitchell made his first appearance of the season from the bench in Saturday's Premiership defeat by Gloucester after missing the start of their title defence and England's entire autumn campaign.

The 27-year-old, who is expected to start in Saturday's opening Champions Cup game with Castres, wants to make up for lost time with next year's Six Nations not far away.

"The worst part to rugby is the injuries," Mitchell told BBC Sport.

"It's been very frustrating watching the games from the sidelines. You have to help the team off the field, but you always want to be playing and I'm so excited to be back.

"I have missed it so much. Sometimes when you're playing all the time your body can feel a bit tired and you might complain about things.

"You maybe don't appreciate it as much, but when you are sidelined it gives you a bit of fire in the belly again and more motivation.

"To have that adrenaline back and to be involved in game day is fantastic."

Mitchell scored the winning try as Saints landed the Premiership title in June and was England's first choice number nine on their summer tour of New Zealand before injury curtailed his progress during pre-season.

"The timing wasnt ideal," he said. "I felt like I was in a good spot and it was such a random injury.

"I got a few bangs during the start of the week on Monday and Tuesday.

"I was fine on the Wednesday but I woke up on Thursday and I couldnt move my neck. I rang the club doctor and he asked me to drive into the club.

"I was in quite a bit of pain in the car but I just thought it would be a spasm.

"It didn't seem to go away and I had to have a scan, which showed it was a bulging disc in my neck.

"I had to have a couple of injections on it and there was no timeline to recovery. The first injection didn't really work but the second one did, so it was frustrating because we didn't know the extent of the injury."