Lions tour manager Gerald Davies confirmed this morning that the Ospreys fly-half will replace Halfpenny, with the latter returning to Cardiff for treatment on his thigh injury.

Davies remains hopeful Halfpenny may be able to join the squad later in the tour while Hook has been pulled out of Wales’ tour to Canada and the United States in order to team up with Ian McGeechan’s squad.

Davies said this morning: “Leigh Halfpenny has returned to Cardiff where he is to undergo treatment for his thigh injury.

“As the injury means he will miss the start of the tour Ian McGeechan and his fellow selectors have called up James Hook to the squad for the tour to South Africa.”

Head coach McGeechan admitted Hook’s ability with the boot was a factor in their decision to select him rather than full back Delon Armitage, a like-for-like replacement for Halfpenny.

“After analysing our requirements for a replacement as we head to South Africa on Sunday we decided that James was the ideal person to come into the tour squad,” he said.

“A very important consideration for us was to strengthen the goal kicking options in the squad.

“James is an accomplished goal kicker and has scored over 200 points for his country in his 33 appearances. Also, he has played at fly half, centre and fullback for Wales but is also comfortable at outside centre.

“He is very familiar with other backs in the squad having played in the same Welsh team as Mike Phillips, Stephen Jones, Jamie Roberts, Shane Williams and Lee Byrne.

“Three of these also play in the Ospreys team with him that also includes Tommy Bowe. Therefore there is an existing understanding between all of these players.”

McGeechan also thanked the Welsh Rugby Union for their co-operation.

“James has been pulled out of the Wales tour to Canada and USA by the Welsh Rugby Union,” he said.

“He was due to leave with them today for Canada but instead James will now join us in camp in Bagshot. We are very grateful to the WRU for releasing James for the British and Irish Lions tour.”

Ospreys star Hook is the latest in a line of replacements following injury withdrawals from the squad.

Yesterday, Scotland hooker Ross Ford was called up to replace the injured Jerry Flannery after the Irishman tore elbow ligaments in training.