BRITAIN'S secret Special Operations Executive tried to sabotage the Second World War mission in Yugoslavia of Brigadier Fitzroy Maclean even before it got off the ground, papers released yesterday by the Public Record Office reveal.

In the event Maclean's support of the Yugoslav partisans, especially Tito, proved to be the most successful operation mounted behind the lines of Axis forces.

Frustrated by the obstructive tactics of his senior SOE officers in Cairo, Maclean confessed that had it not been vitally important to the war effort he would not have hesitated in telling Prime Minister Winston Churchill that he could not undertake the mission.

As it was, days later he parachuted into Yugoslavia not knowing whether SOE would further hinder him by refusing to pass on his communications from behind the lines.

Such was the antagonism towards his mission by senior officers in the SOE Cairo, that Maclean drew it to the attention of Field Marshal Lord Alexander, Middle East commander-in-chief.

He in turn tore a strip off Lord Glenconner, head of the SOE mission in Cairo, at a meeting attended by Maclean and others.

Alexander declared that he had been forced to conclude that the whole SOE operation in Cairo was rotten. He threatened to bring SOE Cairo operations under his personal control by making it a directorate of special operations.

The whole sorry tale of the red tape Maclean encountered from the SOE is revealed in his own hand in the draft of a telegram from him to Sir Orme Sargent, parliamentary under secretary of state at the Foreign Office.

Maclean advises the Minister to do what he thought best with the information it contained - a clear message to pass it on to wartime Prime Minister Churchill.

The SOE attitude is extraordinary. After all, just as Churchill selected Maclean for the Yugoslav task, the special forces unit was set up by him with the instruction to set Europe ablaze. However, while his Yugoslav operation was an outstanding success, most of the SOE's other behind-the-lines operations ended in disaster.

The fact that Maclean had been rapidly elevated to the rank of brigadier clearly did not go down well with his colleagues. In addition they were also perhaps too close to King Peter and the exiled Yugoslav government that had set up home in Egypt. Quite clearly the exiled Yugoslavs could foresee the peacetime danger of Britain arming partisans to fight the Nazis during the war.

Tito ensured that their worst fears were to come true.

In his personal and most secret signal to Sir Orme at the Foreign Office dated August 8, 1943, Maclean reported that on his arrival at Cairo, Lord Glenconner and senior members of staff declared at an initial meeting that they disliked his appointment and frankly stated that they were working to reverse the decision taken on this matter by the Prime Minister, the Foreign Secretary, and the Commander-in-Chief.

They cross-questioned him on interviews he had with General Wilson of GHQ and told him to have no further contact with him, unless sent for. Fortunately, Maclean reported, General Wilson frequently did send for him and was most supportive.

Maclean had also discovered that numerous messages vital to his operation had not reached their destination.

He was under the authority of an organisation which he knew to have been working against him from the start and which did not appear to recognise any outside authority - whether political or military.

Brigadier Maclean, who after the war was to become Sir Fitzroy, declared that no matter what, and even if the situation in Cairo was not cleared up, he was determined not to ''miss another moon'' and would leave for Yugoslavia as soon as possible after September 8.

Indeed Sir Fitzroy did parachute into Yugoslavia within days of sending off the telegram and also had a meeting with Tito.

Meanwhile, the luncheon talk was all about whether or not the British public were entitled to know something that was common knowledge to even the most junior officer in the KGB - that the 1963 head of MI6, who traditionally goes by the title ''C'', was in fact Sir Dick White, newly released papers reveal.

The companions at the meal were the unlikely duo of Colonel Sammy Lohan, acting secretary of the Services Committee on Broadcasting and Press (in other words, the Government's man on the ''D'' notice committee) and Mr David Boulton, editor of the CND magazine Sanity.

''The battlefield was of my own choosing - the Savoy,'' Col Lohan declared in a report on the lunch to A L M Cary, deputy secretary of the Cabinet.

''He arrived, complete with miniature CND badge, reasonably well dressed, with a dark shirt and no tie; I did not spot this sartorial misdemeanour, but the head waiter did and produced a tie.''

Col Lohan was properly dressed although not wearing, as Mr Boulton had thought, a service tie.

The extraordinary dinner date was brought about by an item that originally appeared in Private Eye.

The article, by Mr Claud Cockburn, had identified Sir Dick White as head of MI6. This was something well known to the KGB, but was kept out of the British press through a ''D'' notice.

The article was followed up by Sanity, which not only carried the information disclosed in Private Eye but also published a picture of White's Sussex house. ''The delightful country home of an official secret,'' the caption declared.

The publication of this official secret got up the noses of Fleet Street editors, who wondered whether or not they were now at liberty to name White as head of MI6.

The Government thought not on the grounds that if the movements of the heads of the British intelligence services became common knowledge, then one thing must lead to another.

Clearly, it was reasoned without much logic, it would not be long before their associates also became known and that, in turn, might lead to the whole structure and methods of the intelligence services becoming known to the wrong people.

Fleet Street was prepared to go along, but would such mischievous organs of the likes of Sanity? Hence the Savoy lunch.

Lohan reported to the Cabinet Office: ''I found Boulton a very reasonable person. He agreed immediately to apply my 'off the record' ground rules. He accepted without much resistance my reasons for keeping MI5 or MI6 out of the news.''

Such was the attitude in 1963. In the 1990s, the head of MI5 was arranging photo opportunities.