Farrell admits he endured some "very testing times" last season

The former Great Britain captain made a high-profile switch from rugby league last year but has yet to play a match.

"I can't wait to get started and get the frustration out that has been in me for the last year," he told BBC London.

"Hopefully I will look back on it and laugh as it has been a comedy of errors as far as injuries are concerned."

Farrell suffered a toe injury in pre-season a year ago that required surgery and then suffered a prolapsed disc in his back when a car he was travelling in was hit from behind.

Being injured for so long was a lonely place to be Andy Farrell

He missed the whole of last season as a result but returned to training in early July and is due to begin full contact work next week.

"It has been dreadful really," he reflected. "There is a lot of guilt inside as far as how good the club has been to me.

"These people brought me across to do a job and I have not been able to do anything to repay them yet, that is the frustating thing.

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"Being injured for so long was a lonely place to be, watching the team train and play while you're doing your rehab on your own. They have been very testing times."

Farrell's comeback target is Saracens' first Premiership match of the season against Wasps, part of a Twickenham double-header on 2 September.

"There are still a few things to get through but if I can keep progressing as I have been, I will get there," he said.

Farrell is the centre of attention again as he nears a comeback

He insists it is only once he completes a game of union that he will he give any thoughts to England, who have named him in their elite squad, or the possibility of playing at next year's World Cup.

"It is every player's dream in the Premiership to play in the World Cup, and I am no different," he admitted.

"When you have been down for so long and someone gives you a goal like that to aim for it is very much appreciated.

"But I am just getting back to playing first of all. I am looking forward to being able to sit down after that first game with a lot of relief, and only then will I will start thinking about the rest of my union career.

"There is a lot to do. You can watch all the games you like but there is nothing like getting out on the field and taking the hits, making the tackles and scoring the tries.

"I am going to make some mistakes in the short term and I need to concentrate on correcting those as quickly as possible. Then I can get on with my career."