Clubb, 26, is the Broncos longest serving player and has a year remaining on his current deal but he appears to be looking for a new challenge.
The forward has told Forty-20 magazine that he is ‘sick of losing’. He said, “I am just talking to them (London) about being released and I am hoping they will grant that.”
“I am sick of losing. And that’s what it all comes down to. Losing is not a good feeling. It’s upsetting. It gets to a point where you could cry.
“It’s tough to think that next year I might not be at London but to be honest that is the sport we are in.
“You have to be selfish because you have to do the best to provide for your family.
“I want the challenge of every week being in big games, of being in close, tight games, of winning games.
“I have just turned the wrong side of 25 and I want to push on and get more England caps and be in big games.
“That is where I am in my life and my career at this precise minute so it is tough for me to say but I am going to have to leave London to do that.”
Clubb revealed that London’s record 82-10 defeat by Warrington in Gillingham last month hit him especially hard.
“It affects me as a person and a player, losing by that much,” he said. “I will dwell on it. Losing in general is tough, losing 82-10 is embarrassing.
“I walked off genuinely embarrassed because on top of that it was in my home town in Kent and I had a lot of family there watching. Going in to face them afterwards, it was tough.”