"He excelled as a critic, but, in contrast to Ernest Bevin, creative thought at that time was not his strongest characteristic. He would present any number of difficulties to any proposition which came from official sources, but seldom put forward any constructive proposals of a practical character. ... Aneurin Bevan's speech [to the Trades Union Congress at Brighton in 1933] was typical of him as he was at that time—well-phrased, fluent, tricky, and entirely unconvincing. Bevan was a politician by instinct and temperament and he rightly concentrated his main activities in that sphere. In my experience he exercised a negligible influence on trade union policy and action. How different from Ernest Bevin!"
January 1, 1970
https://en.wikiquote.org/wiki/Aneurin_Bevan