Howley will call time on his international career on Saturday against Scotland after winning his 59th cap, while he can also boast two Lions caps that would have been more but for injury.

The Cardiff scrum-half, who will continue to play at club level, became Wales' most capped No 9 this season when he passed fellow Lion Robert Jones' record of 54 appearances.

"Why didn't he go before he broke my caps record?" joked Jones. "But I am a little shocked - I expected Rob to perhaps finish at the end of next year's World Cup.

"That would have been a great stage to finish a great career.

"But the pressures of international rugby and perhaps the disappointment of Welsh performances of late have made him come to the decision earlier than expected."

Howley has been troubled by a recurring knee injury, the latest concern in a career that has been dogged by injury.

A dislocated shoulder robbed him of probably a starting Test spot for the 1997 Lions in South Africa, while a broken rib ruled him out of the 2001 Lions' third Test and series decider against Australia.

Howley also wants to devote more time to his family, with his wife Ceri who gave birth to their second daughter on Thursday.

His departure from the red shirt will leave a huge hole to fill for whoever is the national coach, whether Steve Hansen's caretaker role is made permanent or the Welsh Rugby Union look elsewhere.

"It's a huge blow for Wales and a big disappointment for Welsh rugby supporters," Jones added.

"The big thing about any scrum-half is his ability to get to a level and then sustain it.

"Rob has managed to do that while playing in fairly mediocre Wales sides, certainly of late.

Jenkins has been sidelined with a knee injury since last year's Lions tour but revealed that he expects to be back in action very soon.

The 30-year-old fly-half added that he has no immediate plans to follow Howley into international retirment but that he would have to "wait and see" how his comeback from injury progressed.

Perhaps the greatest Welsh scrum-half of all time, Gareth Edwards, is also a confirmed admirer of his distant heir.

"Over the last few years Rob has shown he's as good as any scrum-half in the world," Edwards said.

"He's compared and indeed had the best of the likes of George Gregan and Joost van der Westhuizen.

"Rob has an opportunistic ability to spot a gap and score decisive tries, he is very, very quick and powerful on the break and a handful for any backrow."

Terry Holmes, another Wales great who won 25 caps at scrum-half, has coached Howley at club level with Cardiff, although the 45-year-old is now heading the coaching team at Caerphilly.

"Rob will always give you 100 per cent," Holmes said. "He's been a magnificent servant to Wales and he's up there with the best.

"He battled bravely but his body is trying to tell him something and I think it's a good decision on Rob's part.

"But Cardiff might well reap the benefit of Rob's decision to call it a day - he could go on for years yet."

And former Welsh coach Graham Henry joined the list of tributes, saying: "Rob has been a great player for Wales, and a tremendous British Lion.

"He is an outstanding player, and probably one of the best half-backs in world rugby.

"He was captain of Wales during a memorable time for me, and he should be proud of everything he has achieved in the game."