Today's statement from the British, US and Libyan governments follows an interview ITV News did earlier this week with the justice minister from Libya, in which he said he was now willing to cooperate with police in the US and UK.
The Foreign Office has now welcomed that development and said that it looks forward to visiting Libya in the new year and to getting access to information and witnesses to progress their investigation.
Scotland's Lord Advocate has previously said there are still people out there with blood on their hands for this atrocity.
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The lawyers are said to have known their clients were members of the Shia militia and not "the innocent bystanders" that was later claimed.
David Wyeth was carried over the line by Matthew Rees, a stranger who was also taking part in the London Marathon.
A cold northerly wind sweeps patchy rain and showers in across the UK today - particularly affecting northern areas.