Sam Burgess has revealed he stepped away from rugby union because his "heart just isn't in it".

Burgess last week left Bath to return to the South Sydney Rabbitohs as he brought to an early end his time in rugby union to return to league.

The decision, coming so soon after a dismal World Cup for England in which Burgess's performances – and England's decision to select him ahead of Luther Burrell – came under the microscope, has led to recriminations as coach Stuart Lancaster clings to his job.

Burgess has been criticised for giving up on union only a year after his move to Bath, but the 26-year-old insisted it was the best decision for all involved.

“My decision to leave Bath and move back to Australia was for personal reasons, but it was also because I wanted to spend the rest of my career playing the game that’s in my heart,” said Burgess in a column in the Daily Mail.

“Rugby league is in my heart. I’m looking forward to getting back to Sydney, where I’ll be with my family and playing for the Rabbitohs alongside my brothers again.

“Part of me is disappointed to be leaving. Everyone is saying I’ve taken the easy option but it would have been easier to stay and play on in union. I could have just kept playing at six for Bath, but I believe it would have taken about 18 months for me to break into the England team in that position –and my contract is up in about 18 months.

“In sport we have a very limited window in which to compete at the top level and I didn’t want to see those 18 months go by without the same excitement and enthusiasm as the previous 12.”

Burgess said he was keen to rejoin his family, who remained in Australia, and said he was “sorry” for leaving Bath so soon.

“But the way I explained it was that my heart just isn’t in it, and if my heart’s not in it then they won’t get the best performances from me,” he added.

Burgess complained that he felt he had been left to fight an uphill battle given the perception that surrounded his move to union.

“No matter what I did, I always felt that I was fighting a losing battle.

“That was an upsetting factor to me; that people who are supposed to love the game are actually tearing it to shreds. I felt like certain people didn’t want England and Stuart Lancaster to succeed. They were after him – so aggressively. He could never do a thing right, no matter what. I was right in the middle of that and it is unbelievable. It’s not a productive place to be.”