It is widely expected that Home Secretary Theresa May will make an announcement on an independent judge-led inquiry into the murder of Daniel Morgan.
The private investigator was found with an axe in his head in a London pub car park in 1987.
It has been claimed that police corruption prevented the murder from being solved despite six criminal investigations.
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Cloud and outbreaks of rain will ease away eastwards during the morning, clearing the east coast around midday with sunny spells developing.
Police and emergency services are attending the scene.
Rebel-held east remains at risk while the pumping station supplying the western part of the city is once again in operation.