The father of two children allegedly murdered by their mother said he was completely stunned when she left him without warning, a court was told today.

Paul Donnison returned home from work on September 1 2009 to an empty house and a note on the kitchen table from his partner Fiona Donnison, 45.

It read: "Paul, for the sake of the children I feel I have no choice but to move out. I will contact you on Thursday regarding contact with/seeing Harry and Elise. I am sorry. Fiona."

The defendant is accused of murdering Harry and Elise at their rented home in Marshwood Road, Lightwater, Surrey, between January 25 and January 28 last year. She denies both counts.

After the defendant left Mr Donnison he sought legal advice and was told by a solicitor he should keep a diary of what was taking place between him and the defendant, the court was told.

For several weeks Mr Donnison did not know where his children were living as the defendant controlled how, when and where he saw them, it is alleged.

Over the coming weeks the couple attempted a reconciliation meeting at hotels so Mr Donnison could spend weekends with his children. By October he was staying at the house in Lightwater.

By January 14 last year the relationship had irretrievably broke down the couple went their separate ways, the court was told.

The trial continues.