MICHAEL Collins wrote to Dick McKee, Commander of the Dublin Brigade of the IRA, on November 17th, 1920 and finalised the plans for the attack on British intelligence officers on the following Sunday. Collins was brief and to the point: "Have established the addresses of the particular ones. Arrangements should now be made about the matter. Lt G. is aware of things. He suggests the 21st. A most suitable date and day I think."

The note is published in Rex Taylor's book on Collins (1958) and has since been used by almost all subsequent biographers of Collins. Some have changed the information slightly: for example Richard Bennett, The Black and Tans (1959), records that Collins forwarded the names, rather than the addresses; but all writers agree that the role of "Lt G." was of vital importance.

Taylor states that the first contact between "Lt G." and Collins was on June 3rd, 1920. He derived his information from a private source in which "Lt G." is mentioned nine times, and "G" about 17 times. The last note is for July 11th, 1921. Taylor acknowledges that "Lt G." was a leading agent of Collins, and surmises that he was a member of British intelligence in Ireland. Bennett describes him as a "mysterious English intelligence officer", and other authors have. followed their line of identification. Evidence exists, however, to show that "Lt G." did not work for British intelligence. Indeed, he was not even a man. The "Lt G." who worked for Collins at the centre of the British military command, was a woman called Lily Mernin.

Piaras Beaslia provides the club - that reveals the identity of "Lt G.". In his "Memories," published in the Irish Independent in 1965, he wrote of a relation of his, Lily Mernin, who was born in Dungarvan. She came to Dublin where she found work as a typist, and soon secured a position with. the British army.

Tim Pat Coogan states that she was the secretary of Major 5.5. Hill Dillon, chief intelligence officer at Parkgate Street. On duty she wore khaki off duty she was a member of the militant Keating branch of the Gaelic League. Beaslai renewed contact with her towards the end of 1919 and informed Collins of his association. Collins interviewed her and immediately realised that she was a potential source of priceless information. So important was she that she was given a key to a small room in a house in Clonliffe Road where a typewriter was placed at her disposal. She went there regularly to type up reports and to pass on documents.

COLLINS wanted news particularly of officers living in civilian dress outside barracks, and Mernin provided this information. Beaslai maintained that "the list supplied by Miss Mernin was largely used in the operation of Bloody Sunday". He wrote that "Collins was continually sending me notes: `Have you seen the little gentleman. We want to hear from him'." Here we have the key that unlocks the door: "Lt G." did not signify military rank, but was the abbreviated form of "Little Gentleman," and that gentleman was Lily Mernin.

Mernin's assistance to Collins related especially to the challenge from British intelligence posed by the appointment of Brig Gen, Sir Ormonde Winter as chief of the combined intelligence services staff in May 1920. Winter was instrumental in setting up a school of instruction for suitable agents in England. Dressed in civilian clothes and living outside the confines of Dublin Castle, they set out to infiltrate the spy network of "Collins and to eliminate his agents. It was to identify these men that Collins turned to Mernin for help.

Mernin made a significant contribution in September, 1920. In the early hours of Wednesday, September 22nd, 1920, John Lynch was shot dead in the Royal Exchange Hotel in Dublin. He was the principal clerk of John Power the solicitor who was preparing the defence of the Knocklong prisoners. Both Lynch and Power were from Kilmallock, Co Limerick. Soon afterwards, Michael Collins received a report from "Lt G." giving details of the shooting. Collins was able to inform Arthur Griffith that: "at 1.35 a.m., on the morning of the murder, a phone message was received by Captain Baggally, General Staff, Ship Street, Barracks". Collins added that Baggally had then instructed a car to collect members of the RIC and the military who had carried out the shooting. Soon afterwards Mernin informed Collins that Lt Angliss, operating under the alias of McMahon or Mahon was directly involved in the murder.

Over the next two months Collins, with the help of Mernin and other sources, built up a list of "British agents. The list was scrutinised by Cathal Brugha, Minister of Defence, and the GHQ of the IRA. Some names were removed and those remaining were the targets for Collins's Squad and the IRA on Bloody Sunday.

The attacks on the British agents began at 9 a.m. on Sunday November 21st. Fourteen were to die, among them were. Baggally and Angliss. Collins informed John Power, the solicitor, that "we got those responsible for the death of Jack Lynch". The military records reveal that several of the men had engaged in intelligence work abroad: Angliss on the Russian front; Capt McLean in Holland; Capt Bennett in the region of the Black Sea; Capt McCormack in Cairo; and Lt Col Montgomery was a senior naval intelligence officer. Others who were killed or wounded were experienced intelligence agents. The importance of those killed was admitted in the official Record of the Rebellion in Ireland when it stated, that "the murders of 21 November temporarily paralysed the special branch. Several of its most efficient members were murdered and the majority of the others resident in the city were brought into the Castle and the Central hotel for safety."

Collins had good reason to be grateful to Lily Mernin for the success of Bloody Sunday. She, for her part, went to confession in the Pro Cathedral, where she was told that she was acting properly in helping her country's soldiers against a ruthless enemy. She was dismissed from her post at the signing of the Truce on July 11th 1921, the date given by Rex Taylor as that of the final message sent by "Lt G" to Michael Collins. Lily Mernin, the "Little Gentleman," was not able to provide any more assistance.