YOU report on a new plea by the Liberal Democrats for a public inquiry into the Lockerbie bombing and back it up in your leader as "a welcome step towards shining new light on exactly what led to the death of 270 people on December 21, 1988" ("New plea by LibDems for Lockerbie public inquiry", The Herald, January 3).

There are two possible strands to such an inquiry: first, with the co-operation of the Libyan government, a clarification of its role. This may, we hope, be forthcoming.

The second strand would be the earlier sequence of events following the shooting down by the US battlecruiser Vincennes of the Iran Air flight 655 on July 3, 1988, causing the loss of 290 crew and passengers, most bound for Mecca and the Hajj.This was the first focus of US suspicion and, I gather, the CIA acknowledged that the terrorist group PFLP-GC, led by Ahmed Jabril, had offered its services to the Iranian government to avenge the Iranian deaths.

The first strand may (or may not) lead to the conclusion that Abdelbaset Ali Mohmed al Megrahi was not guilty of participating in the bomb plot to down Pan Am Flight 103, but it is very unlikely, if not impossible, to establish an alternative explanation without the full co-operation of the US Government and security services, notably the CIA. I suggest that, in the light of intense US public hostility to the possibility that Megrahi might not be guilty, as well as the conspiracy of silence which might be exposed by an alternative explanation, I am not convinced that the time and expense of a full public inquiry could be justified.

Christopher Frew,

320 Leith Walk, Edinburgh.