Mick Philpott tells the jury he didn't tell police that his friend Paul Mosley had had sexual relations with his wife Mairead because he was "ashamed".
He also told the court he felt it had no relevance to what had happened to his children on the night of the fire.
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Initial indications were that the test on Friday was unsuccessful, according the a US government source who spoke to Reuters.
Southerly winds will bring warmer temperatures this weekend. Rain arriving on Sunday.
A cancer-stricken young father who may have just weeks to live says he refuses to "roll over and die" - and has launched an appeal for help.