Tania Clarence, the woman who smothered her three children to death, wrote a letter to her husband explaining why she had done it.

Gary, I need to tell you how difficult it is for me to take Liv’s life. I am so ghastly and I feel every ounce of it for doing this.
The boys were bad enough. I am struggling with Liv. I waited until the boys were asleep. The same with Liv. If I could take my own life and leave her to wait for you I would. But the wait will be as traumatic.
This is so bad and I am so, so sorry. My only solace is that pain and future suffering I am saving her from.
My only solace is the pain and future suffering I am saving her from. I am so sorry…
The only thing giving me the motivation to continue is the belief that the boys are already playing up in heaven like they could never play here.
I cannot face going down this path watching Liv and the boys continue to get weaker.
Most importantly, the interference in our lives (you know: GOSH [Great Ormond Street Hospital], NHS, Kingston/Moor Lane). I am tired of it all. No matter what we overcome, no matter what we do, it will never be enough.

Tania also handed another note to the nanny, Jadna Coelho (known to the family as Jade):

I am so sorry I had to do this but I could not carry on. I also could not leave the children with Gary. It would have been too much for him.
You have been the most amazing person in our lives over the last few years. Without you I most likely would have done this a lot sooner. Please don’t think that there was anything more you could have done to avoid this.
Please believe me when I say that you did far too much as is. There was nothing more you could have done. You were/are perfect. I am so sorry I had to end things this way. Please look after Taya for me. Taya and Gary still need you (very much).

After listening as the letter was read out in court, Tania broke down in tears and was taken back to hospital.

Read more about the case at The Daily Mail