The documents and emails were written by then party leader Don Brash, and a wide range of people associated with him.

In particular, he denied receiving a crucial e-mail on 25 May 2005 that spelt out Exclusive Brethren election plans and their co-operation with the National Party.

[8] However, Hager's book also detailed that, on the same day as the Exclusive Brethren's letter was sent, Brash had sent another email in which he discussed the possibility of other groups funding "parallel campaigns" that would benefit the National Party.

[9] Brash wrote a response to the book in December 2006 that claimed to show "dozens of factual errors, some of no great significance but others of much greater importance".

In particular, he identified "the allegation that taxpayers' money was used to pay for a pamphlet promoting a fair tax regime for the racing industry; it was not."

"[10] In response Hager wrote that "out of a 350-page book, with nearly 1000 detailed references, Don Brash has found two minor inaccuracies.

"[12] An internal review of the original investigation was conducted by the New Zealand Police as a result of complaints lodged by Brash.