Great Britain will need to find an alternative hooker this autumn following the announcement of Keiron Cunningham�s international retirement.
The 29-year-old has long been rated as the world�s best hooker and his withdrawal is a blow for Lions coach Brian Noble.
"I�m at the stage where I feel I should be concentrating on my club rugby," Cunningham told the Sunday Mirror.
"I have explained the situation to Brian Noble, who hopes I will reconsider my decision, but at this stage I will not be going."
Cunningham has enjoyed a fine career with Saints but his international appearances, however, have been sporadic due to injuries and last autumn�s Tri-Nations games were his first for the Lions in three years.
Cunningham, who has also played for Wales, made his Great Britain debut against Papua New Guinea in 1996 and won the last of his 16 caps against New Zealand in June.
Cunningham had been a member of Britain�s �train-on� squad preparing for the Tri-Nations Series. Bradford Bulls' Terry Newton will be the favourite to assume his position but there could also be opportunities for Mickey Higham of Wigan Warriors or the recently called up Malcolm Alker from Salford City Reds.
Cunningham is contracted to Saints until the end of next season and says he has not ruled out the possibility of a move to Australia."Clubs have already been in touch and playing in Oz is something I've always wanted to do," he added.