The letters sent by Tony Blair and George Bush shed light on the relationship between the two in the run-up to the Iraq War.
Here are the key exchanges in the 29 memos released as part of the Chilcot Inquiry.
"I will be with you, whatever"
Tony Blair privately assured George Bush he would support him with "whatever" when it came to dealing with Saddam Hussein.
"We still need to make the case" for toppling Hussein
Blair said the case could be made using WMD evidence, Hussein's attempts to secure nuclear capability and the "possible" Al Qaeda link.
"Regime change is vital"
Blair said "swapping one dictator for another seems inconsistent" and regime change must provide stability.
"We must have a workable military plan"
Blair outlined what he thought the best ways to topple Saddam Hussein would be.
"Our best ally might be Russia"
Blair said public opnion in the US is "quite simply on a different planet from opinion here".
Mr Blair frankly admitted that he could not guarantee support in Britain for his plan - even among members of his own government - and noted that international public opinion was likely to be strongly opposed.
"If we win quickly, everyone will be our friend. If we don't and they haven't been bound in beforehand, recriminations will start fast," he wrote.
"In my opinion, neither the Germans or the French, and most probably not the Italians or Spanish either, would support us without specific UN authority... "And - and here is my real point - public opinion is public opinion. And opinion in the US is quite simply on a different planet from opinion here, in Europe or in the Arab world."
The document - dated July 28, 2002 - is among 29 letters and notes sent by Mr Blair to Mr Bush between 2001 and 2007 to be released by the inquiry.
However, the Chilcot report does not support claims by Mr Blair's critics that he agreed a deal "signed in blood" to topple Saddam with Bush in April 2002.
Instead, in his letter, Mr Blair set out a strategy for presenting Saddam with an ultimatum demanding he admitted UN weapons inspectors back into Iraq in the expectation that he would "screw up", providing a cause for war.
In his letter Mr Blair acknowledged there would be "reluctance" in the US about taking the issue of the Iraq invasion to the UN Security Council, but insisted it was the best way to provide them with a legitimate case for military action.
"We don't want to be mucked around by Saddam over this, and the danger is he drags us into negotiation.
"But we need, as with Afghanistan and the ultimatum to the Taliban, to encapsulate our casus belli in some defining way," he wrote.