I can't understand how Hague can do this (or rather that this is legal), it totally undermines the British justice system; do the Russians really have that much of a hold over 'us' ?
http://www.guardian.co.uk/world/2013/may/17/litvinenko-coroner-crucial-evidence-secret?CMP=twt_fd
The inquest into the death of Alexander Litvinenko is close to collapse after a coroner partially upheld an application by William Hague to keep crucial evidence secret.
The coroner, Sir Robert Owen, reluctantly agreed to exclude material from the inquest that suggested Russian state agencies were involved in Litvinenko's death. He also agreed to keep secret evidence that considered whether or not the UK authorities could have prevented Litvinenko's 2006 murder.
...
The foreign secretary applied for a PII certificate on 7 February. He argued that if secret evidence were revealed it might damage "national security and/or international relations". He gave no further details.
http://www.guardian.co.uk/world/2013/may/17/litvinenko-coroner-crucial-evidence-secret?CMP=twt_fd