As Mosher and Fuller noted in The CRUTape Letters, in the first years of the twenty-first century relations between Phil Jones and Steve McIntyre were relatively collegial. However, something changed during 2003 and thereafter Jones adopted an approach of blocking all McIntyre's requests for data.

It's hard to tell exactly what prompted this change of heart - the two major events of 2003 were the Soon and Baliunas affair and publication of MM03. Since both of these were critiques directed at Mann, it's not obvious why they would affect Jones. Clearly Jones had to be persuaded that there was a group interest in resisting McIntyre's efforts and in email #1566 we get a taste of how this was achieved. In it, Mann tells other members of the Hockey team about an email he has just sent to McIntyre, telling him that he will not respond to further requests for information (see The Hockey Stick Illusion p.91).