Rebekah Brooks and Andy Coulson, the two former editors of the News of the World at the centre of the phone hacking trial, had an affair lasting at least six years, the Old Bailey has heard.

Brooks and Coulson, the two principal defendants in the case, were involved in an adulterous love affair between 1998 and 2004 at least, the jury was told after a deeply intimate love letter was found on Brooks's computer in 2011 by police.

Brooks continued her affair with Coulson for two years after marrying former EastEnders actor and Sky 1 presneter Ross Kemp in 2002. They divorced in 2009. In the same year, she married Charlie Brooks - who is appearing alongside her in court on a charge of perverting the course of justice.

Coulson married Eloise Patrick in 2000 and continued seeing Brooks behind his wife's back for four more years. Coulson and Patrick have two children.

The letter, written when Coulson broke off the affair, brought to the attention of the jury by prosecuting counsel Andrew Edis QC, also revealed insights into the fear that Rupert Murdoch, the boss of News International (now called News UK), instilled in his top editorial executives.

This is the extract read to the jury:

"Finally, and the least of our worries, but how do we really work this new relationship? There are a hundred things that have happened since Saturday night that I would normally share with you, some important, most trivial.

The fact is you are my very best friend. I tell you everything, I confide in you, I seek your advice, I love you, care about you, worry about you. We laugh and cry together. In fact without our relationship in my life, I am really not sure how I will cope.

I'm frightened to be without you, but bearing in mind 'the rules' you will not know how I am doing and vice versa.

The thought of finding out anything about you or your life from someone else fills me with absolute dread. Also you said I had to email you if anything important happened, like if I was ill?

I don't understand this, we are either there for each other or not surely? Anyway, that really isn't where I am confused. I know what horror it means and I know why we have to stick to it.

But for example, how does this work thing manifest itself. Do we limit contact until we absolutely have to, like leaving our execs to sort run-of-the-mill joint stuff? I don't want to get this wrong.

I hope that I've managed to put your mind at rest about Les [apparently Les Hinton, at the time News International's executive chairman], and that you two now have a better relationship.

On KRM [Rupert Murdoch], well he's not bollocking you, you must not brood on lack of calls. Obviously I can't discuss my worries, concerns, problems at work with you anymore, and vice versa, but I'll assume unless I hear different that we keep our professional relationship to the minimum, and avoid if possible without it being in any way awkward.

If it is necessary or more importantly right that we two editors should deal with it, then we will. If either of us feels that we are not striking this balance then we must say."

Ross Kemp
Rebekah Brooks penned love letter to Andy Coulson whilst married to Ross Kemp (above)