As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
AIRCRAFT WAS GROUNDED: AN EMERGENCY WAS DECLARED DUE TO CREW O2 DROPPED FROM 1410 DEPARTING LHR TO 1250 PSI. AIRCRAFT DIVERTED TO KEF LANDING SAFELY. ACCOMPLISHED SATISFACTORY LEAK CHECK PER AMM 35-00-00. REPLACED CREW OXYGEN BOTTLE PER AMM 12-15-08.