Llanfairfach Incident

From Tardis Wiki, the free Doctor Who reference

The Llanfairfach Incident was a level three incident which was documented in a top secret file from UNIT, dated 17 June 1973. Exactly 30 years later, UNIT made their documents public. The document mentioned Clifford Jones, Brigadier Alistair Gordon Lethbridge-Stewart, Jo Grant and UNIT's mysterious scientific advisor, "Dr John Smith". (HOMEVID: Global Conspiracy?)