She has seen no fewer than 17 party leaders come and go and now she wishes to depart too. Announcing this fact to the House, Madam Speaker presented it as a timely bow from a distinguished public servant, and set off a series of glowing testimonials from all sides of the House, members competing with each other to hymn Miss Tanfield's virtues.
Tony Benn won easily, describing her as "the custodian of the collective experience of the human race", which I thought was pushing it a bit, frankly, until I realised that he was talking about librarians in general.
It sounded like the perfect retirement - honoured, appreciated, warmly- waved goodbye - but I did wonder whether Miss Tanfield might actually have left in despair, forced to give up the job she loves by the systematic undermining of her work by the Prime Minister. Because almost the only other occasions on which the library is mentioned - apart from when ministers fudge a tricky answer by promising to deposit some papers there - is when an Opposition member waves incriminating statistics at the Government front bench.
Mr Hague did it yesterday, clutching a sheet of paper from the library researchers which, to his satisfaction at least, nailed the Government's failure to keep its promises on class sizes. Mr Hague had brought a mug to back him up (yes, yes, I know, he'd brought around a hundred) but this one was a Labour Party mug - a bright red thing blazoned with the words "Class sizes down".
This, Mr Hague suggested, waving it across the dispatch box, could finally be seen for what it really was. Not an innocent fund-raising novelty, but a mendacious mug. And the proof of that damning accusation came from the House of Commons library, a source Mr Hague cited as if it was as unimpeachable as the voice of God. "Again, he is wrong," Mr Blair replied starkly, as he has done on several previous occasions when taxed with the figures on class sizes or the real state of NHS waiting lists. He can't have meant Mr Hague was wrong, of course, since Mr Hague was only passing on the bad news. Mr Blair meant the House of Commons Library was wrong, and, by extension, Miss Tanfield, ultimate arbiter over its operations. Well, he won't have her to kick around any more.
Hers wasn't the only retirement celebration yesterday afternoon. When Mr Ashdown rose to put his last two questions to the Prime Minister there was a solid roar of acclamation, even the waving of order papers, rather than the moan of disapproval with which the more boisterous MPs traditionally greet the arrival of this disapproving grown-up. "Yes, yes," said Mr Ashdown indulgently, relishing the unfamiliar sound, "and I shall miss you too." His valedictory questions were sharp ones - we had promised 3,000 policemen in Kosovo, he reminded the Prime Minister, but there were currently only 70 on the ground.
Mr Blair clearly did not begrudge him his last flare of constructive opposition. He sent Mr Ashdown away with a wreath in his hair - paying tribute to the "tremendous contribution he's made to British politics" and acknowledging that on Yugoslavia he was "well ahead of the rest of us and right before the rest of us". Miss Tanfield will have to settle for the undemonstrative nod Mr Blair added to others' tributes, guilty as she is of having given succour to the enemy.Reuse content