He always did keep fit. For years, when director of music at King's College, Cambridge, Willcocks frightened the life out of undergraduates under half his age on the squash courts. Staying young at heart never was a problem. Buried deep in an anonymous personal archive, I am assured, is a tape of him singing Lennon & McCartney's Yesterday approximately three octaves too low. Just for a giggle.
It turns out that the only frustration tempering his decades of devotion to the Bach Choir has been the blessed nuisance of having to be in London for Monday-evening rehearsals. "That's stopped me from accepting all manner of trips over the years. Now I have the chance to take on a few more of them." I'll say. The least strenuous thing I can see in his schedule is picking up an honorary degree in Iowa. Although Willcocks's association with King's ended a quarter of a century ago, when he left to become director of the Royal College of Music, there are many parts of the world where the connection remains potent through recordings and folk-memory. To so many, Willcocks remains the arch-exponent of the quintessential Anglican choral sound - those ever-so-slightly arch vowels included.
Willcocks took up his appointment at King's in 1957 (providentially, just as stereo recordings were coming into their own) with the classic hassock-cassock pedigree: choirboy at Westminster Cathedral, organ scholar - yes, at King's itself - organist at Salisbury and Worcester cathedrals. Three years later, in March 1960, the grande dame among British concert agents, Emmie Tillett, phoned out of the blue to say that the Bach Choir's legendary conductor, Reginald Jacques, had suffered a heart flutter and decided to call it a day. Was Willcocks interested in the idea of taking on the last concert of that season? It was a question of those blessed Monday-night rehearsals, of course - "but I was free for them all and delighted to accept the offer".
The Monday nights became a fixture, although at first the Jacques era cast a shadow. "The older singers were very kind to me, but in their heart of hearts I think they wished `J' was still there! In fact there was rather an elderly look about the choir... Perhaps my successor David Hill will feel the same!"
There was no vicious weeding-out process (not his style) but Willcocks soon began the process of introducing new blood - a regular transfusion service, no less. With his Cambridge post had come the job of conducting the choir of CUMS, the university musical society. Maggie Heywood is one of dozens of CUMS members who over the years took up the invitation to extend their Willcocks connections - assuming they were free on Monday evenings. "Sir David's joke was that he had the permission of the Bach Choir conductor to audition us. With him in charge, both choirs took on the atmosphere of large, happy families, although I reckon he told CUMS the more risque jokes!"
Ah, yes... Does the Bach Choir have the reputation of being just a shade, well... "Snooty?" Sir David helps out. "I think that's simply because we've had the Prince of Wales and - still - the Duchess of Kent in our ranks, and we've sung at a number of royal occasions, such as the 40th anniversary of the Queen's Coronation. But, in the main, we're no different in our personnel to any other London chorus. What I do know is that the singers are exceptionally dedicated - the Bach Choir plays such an important part in their lives. The attendance record at rehearsals is extraordinary."
Dedication has been warmed by the discipline. Willcocks has never been a soft touch when it comes to tuning and rhythmic precision, but, says choir member Marion Needham, he always makes hard work fun. "He'll get one half of the choir to judge if the other's in tune. He makes you listen to other parts - for example, when we're rehearshing fugal passages, the singers with the fugue subject will be made to stand up - simple, but very effective."
"He has a way of dancing the rhythms as he conducts," says bass singer Christopher May. "One of his great gifts is being able to make this large choir really light on its feet."
Never lighter than in the yearly performances of the St Matthew Passion on London's South Bank, quintessential Bach Choir occasions that have held their own in terms of public affection even as the early-music brigade has stolen Bach away. So, has fashion changed Willcocks's way with this masterpiece over the past 38 years? "Imperceptibly, I think! But Bach can be performed in so many different ways, not least in the concert hall with a large choir - after all, Bach worked with whatever forces were available to him."
Unsurprisingly, given the Willcocks wanderlust, he counts the Bach Choir foreign tours as major highlights. These brought a new dimension to the choir's life during his reign - previously, travel even outside London had been a rarity. "On tour, you can really get to know members of the choir - and, of course, we've had the opportunity to sing in some marvellous places. There were the first performances of Britten's War Requiem in Italy, at La Scala in 1963; Walton's Belshazzar's Feast at the Concertgebouw in Amsterdam; the opening of the new cultural centre in Hong Kong." Not to mention trips to Australia and New Zealand, the USA and South Africa, where the choir was the first of its kind to tour since the collapse of apartheid.
"Particularly when we go abroad, I feel we have a responsibility to perform British music. Generally speaking, it goes down very well, although the one mystery to me has been the fact that Elgar seems to travel rather badly." A Dream of Gerontius performance later this year at the National Cathedral in Washington DC, though not with the Bach Choir, will perhaps help put that right.
Willcocks disputes the notion that the choir has been cautious over adventurous repertoire. "Right at the start of my time we did Fricker's The Vision of Judgement... Two years ago we gave the London premiere of the Penderecki Te Deum. But, like everyone else, we've had to weigh up what we can afford to do as far as the box-office is concerned."
The future of choral singing in the UK will remain a prime concern. Willcocks is keen to do all he can to help promote singing in schools - "over the next 20 years," he adds with a grin. "Cost-cutting has been so much in the headlines; we need to support and encourage music teachers, especially as it's been shown that music can sharpen the intellect and is a marvellous focus for collective activity. Not every parent can afford to buy their child a musical instrument, but almost every child can sing."
Willcocks's successor at the Bach Choir, David Hill, has something of a head start. Prior to his current full-time post as organist of Winchester Cathedral, he was Master of Music at Westminster Cathedral. "On Monday evenings the sound of the Bach Choir rehearsing in Cathedral Hall would waft through to where we were celebrating Mass! It's a choir of musicians, first and foremost - you see that in the astonishing sight-reading. In Sir David's time, standards have risen phenomenally."
Willcocks's last concert with the choir, a Good Friday performance of the St Matthew Passion in Symphony Hall, Birmingham, will wrench the emotions. Breaking with jobs has been been like ending love-affairs throughout his career - not for nothing is "Valentine" his middle name. What he will miss about the Bach Choir, he says, is "making music with friends. There's nothing in the world more pleasant than that."
St Matthew Passion: 11am Sun 29 March and Sun 5 April, RFH, SBC, London SE1 (0171-960 4242); 2pm 10 April, Symphony Hall, Birmingham (0121 212 3333)