Former police officer Alan Tierney, from Hayling Island, Hampshire, has been released on bail after admitting to selling information about the arrests of John Terry's mother and Rolling Stone Ronnie Wood to the Sun newspaper.
Tierney will to be sentenced on March 27. Mr Justice Fulford, sitting at the Old Bailey, warned him that "all options remain open". Tierney pleaded guilty to two counts of misconduct in public office.
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Among those expected to attend the ceremony will be former US President Bill Clinton and ex-Northern Ireland first minister Peter Robinson.
Five people have been killed and 40 injured after a car and knife attack in London on Wednesday.
A wet, wintry night in places with rain and hill snow slow to move away from southern Scotland and northern England.