"We don't really talk off the field," Back said."We have a silent respect for each other." Both are old fashioned tearaway flankers. They may not win possession in the line-out but their speed provides a vital link between forwards and backs. By nature they are attacking players and also decisive tacklers.
"Andy is a bit smaller than me although he wouldn't like to hear it," Back said. "In any case, size has nothing to do with it. You're either good enough or you're not."
The other thing they have in common is that both have been rejected by England. Jack Rowell, the manager, himself a former back row forward of the extra large school, believes big is beautiful although he had a re- think following the annihilation of the England back row (Tim Rodber, Dean Richards and Ben Clarke) in the World Cup semi-final against New Zealand in Cape Town last summer.
Back to the future? It did not work out like that. "Jack said he would revert to an out and out open-side flanker for this season and that took huge pressure off me," Back said. "I thought at long last I'm no longer competing against the back row giants. I felt relaxed, confident." Back took another kick in the teeth.
For the game against South Africa at Twickenham last November, Rowell went for an out and out open-side but it was not Back it was Robinson. "Andy hadn't been in the England squad for five years so I was totally bemused," Back said. "It has never been explained to me. I had a conversation with Jack but it wasn't very constructive. Although I was confused I wasn't disheartened because Andy and I are of similar stature and I still thought there was a place for me."
He thought wrong. Out went Robinson - "I thought he had a good game against the Springboks," Back said - and in came the towering figure of Lawrence Dallaglio. For the first time since 1985 Back is not part of an England squad although he played for his country in the Hong Kong Sevens. He has been through the lot - England Under 18's, Colts and the B team before winning his first full cap against Scotland in 1994.
It was the first of only five. No sooner had he established a place for himself in the World Cup, playing in the victories over Argentina, Italy and Western Samoa than he pulled a hamstring. "I've been playing rugby for 20 years and that's the first muscle I've ever pulled. The timing couldn't have been worse. Things were going really well and I'd have probably played against Australia in the quarter-finals. Instead the big men came back into Jack's head."
England, of course, beat Australia with Rob Andrew's famous drop goal but were hammered by the All Blacks and Back thought he would win back his place for the third-fourth place play-off against France. Again he thought wrong and Rowell kept faith with a jaded team. "That was terribly disappointing," Back said, "but I've got a strong chin. I've taken enough knocks."
This season Back, at 5ft 10in an inch or two taller than Robinson, has built himself up to 14 and a half stone, putting on 12lb. He worked with a personal fitness adviser on a 12-week programme. "I wanted to become more powerful but it was more of a psychological thing to make the selectors think I was bigger and better. In fact I'm not the fittest I've ever been."
If that curious blond mane (a cross between a floppy wedge and an Eton cut - the man to blame is his elder brother Ian, a hair stylist) has been less in evidence this season it is perhaps down to the Leicester style and more responsibility at work. Back, who is 27, heads a team of 12 as a personal pensions supervisor. "The balancing act between work and play is becoming very tough. I've got five good years left in rugby. I still want to play for England and Leicester and when that's over I want to concentrate on my job."
He has not yet signed with Leicester, whom he joined in 1990, and has had offers from other clubs. "I love Leicester and that's where I want to play. I want a contract that will enable me to give 100 per cent. Leicester are not getting 100 per cent of my potential if you know what I mean. I hope my employers can give me a position which will allow me to devote more time to the game."
Today a forward called Back promises to "throw everything at it". "It's a huge opportunity to show the world what we can do. A more fluid game would suit me and that's exactly how we train. It's going to be very physical, very ferocious, very fast and very close."