Ignorance rather than perfidy
Attlee's government faced enormous economic, social and geopolitical problems in its first term of office and gained great respect for its vigour and effectiveness – as did Attlee himself, who has come be regarded as the most successful of all 20th century peace-time Prime Ministers – and as a thoroughly decent, honourable chap. Indeed, Margaret Thatcher herself, though of opposite political persuasion, held him in the highest possible estimation – "All substance and no showiness", she said of him admiringly. I suppose he was our equivalent of Harry Truman.
Attlee's Foreign Secretary Ernest Bevin had been Minister of Labour (ie manpower) during the war and had no first-hand knowledge of the course of events in the Far East, let alone of the immense contribution made by the Karens in winning the ground war against the Axis. If he had been briefed by senior civil servants he'd probably have been advised that the Karens were a troublesome bunch of separatists out to scupper the London conference in 1947 in which he and Attlee handed over the whole of Burmese territory to Aung Sang and his power-hungry henchmen.
And indeed, during the subsequent Karen insurrection in 1949, Britain sent military assistance to the Burmese rather than to the Karens – who were still reliant on the ageing weaponry with which sympathetic British officers had privily provided them at the end of the war.
Labour barely survived the next general election in 1950, lost in 1951 and again in 1955. Attlee resigned, accepted an Earldom and took his place in the House of Lords – in which great issues could still be freely debated and publicised.
And it was as Lord and Lady Attlee that they took a motoring holiday in Ireland a year or two later and stayed for a fortnight at Ardnagashel House Hotel, run of course by Ron (and Audrey) Kaulback! What an extraordinary coincidence, and unrivalled opportunity for Attlee to hear for the first time, and at first hand, about the injustices done, and broken promises made, to the Karens.
Except that it didn't happen, and probably couldn't have happened. The social conventions that still prevailed, and probably the Official Secrets Act by which he was bound, plus the sheer daily slog of running the hotel, precluded Ron from broaching such a controversial subject with such a distinguished elder statesman.
Sonia well remembers, however, that her twin brothers Peter and Bryan, at about nine years old the two youngest members of the family, regularly prevailed on Attlee to play Scrabble with them, at one of the spacious window seats of the drawing room. I'm sure that he would have proved the kindliest of opponents!