Can someone explain yesterday at Leveson to me?

Gordon Brown’s appearance at the Leveson inquiry yesterday included being questioned about what his staff got up to with undermining other Labour figures.

This garnered a response from him that – most charitably – can be described as not widely believed. It also contradicts many other accounts given of his time in office.

So – if this issue is not relevant to the Leveson remit, why was it raised? But if it is relevant, why was his answer simply taken at face value and the inquiry moved on without testing out its accuracy or asking why so many other accounts contradict it?