British Prime Minister David Cameron sent an intimate text message to Rebekah Brooks thanking her for a "fast, unpredictable and hard to control but fun" ride on one of her family's horses.
The message, which could be read as suggestive, and another from Brooks to Cameron were disclosed to Lord Justice Leveson but were going to be kept secret, sparking claims of a cover-up by the inquiry and Downing Street.
They were revealed by the Mail on Sunday yesterday just weeks before Leveson is due to publish his report into the phone-hacking scandal which triggered Brooks' resignation from Rupert Murdoch's News International.
Chris Bryant, the Labour MP, has been pressing the Prime Minister in the Commons to reveal details of what he called "salacious" emails and texts between him and Brooks, whose husband, Charlie, is an old friend of the PM. Cameron has refused to respond to questions from Bryant, and No 10 has insisted that it has given the Leveson Inquiry all "relevant" documents.
Both texts revealed yesterday were sent in October 2009, weeks after the Sun switched support from Labour to the Tories. Cameron's text to Brooks read: "The horse CB [Charlie Brooks] put me on. Fast, unpredictable and hard to control but fun." He signed off "DC".
In the second, sent after his speech to the Tory conference, Brooks also made an apparently ambiguous remark by writing: "Brilliant speech. I cried twice. Will love 'working together'."
Brooks is awaiting trial next year on charges of phone hacking and conspiracy to pervert the course of justice.
There are other texts and emails that have been handed over to the Leveson Inquiry but have not been made public because they are not deemed "relevant".
The messages were revealed at the end of another difficult week for the Prime Minister, during which he was defeated by 53 Tory rebels over a cut in the EU budget. There was also a suggestion that his chief strategist and polling guru, Andrew Cooper, is on the verge of leaving, a move which would cause further upheaval in the beleaguered Downing St operation following a series of departures of key staff.