Police have been given more time to question 10 people held on suspicion of PC Andrew Harper's murder.
A 17-year-old boy is charged with murdering "devoted father" Peter Duncan in Newcastle.
A Coastguard helicopter is helping fire crews and police looking for the child in the River Stour.
But Oliver Letwin urges talks in the Commons to prevent the UK crashing out of the EU without a deal.
The chancellor says he is a "low tax guy" and he wants to see "simpler" taxes when he delivers his Budget.