Within these sacred halls

The title is the first line of Sarastro's simple but sublime aria of consolation to Pamina, who's just been terrorised by a hellbent mama, in Mozart's Die Zauberflöte. William Mann paraphrases the sentiments very beautifully in his The Operas of Mozart: 'We do not know revenge in this holy place. If someone falls, he is raised up by love and friendship to better things. Traitors cannot survive when all people love one another and treachery is forgiven. Anybody who does not appreciate this is unworthy to be a human being'.

Mann adds: 'this two-stanza strophic song is essentially the creed of Sarastro's Temple and of the Freemasonry which Mozart and Schikaneder [his librettist, manager of Vienna's Theater auf der Wieden where The Magic Flute opened in 1791 and the first Papageno] embraced'. Mozart is on the far right, it seems fairly clear, of the below painting of the Viennese lodge Zur neugekrönte Hoffnung, 'Of new-crowned hope'.' It is, I hope,' Mann adds, 'the basic creed of everybody, no matter what ethical faith they subscribe to.' And therein lies the noble essence of what Freemasonry originally was, and what it still purports to be: 'a craft, a personal vocation of benevolent moral growth, whose principles are conveyed through imagery connected to building'.

Those words are from Tim Dedopulos's The Secret World of the Freemasons, an excellent if uncritical introduction, though misleadingly titled; there are no secrets other than the password or gesture used to identify members of one lodge to another,l and since Mozart's time the rituals have all been divulged in print. I found sentences like that useful in trying to understand the fundamental benigness of a movement which is neither a cult nor a religion in itself. What a pity Freemasonry has become a byword for nepotism and ganging-up within interconnected professional movements like the police and the law when - Dedopulos again - 'the society's oaths and obligations specifically forbid members from using the organisation in this way'. There is, alas, plenty of evidence to prove that they do.

One thing's for sure - the lodges in this country, each with its independent rules and rituals, have made every effort in recent years to open their doors to the public; we saw an early example on a King's Lynn Architecture Open Day some years ago. Freemasons' Hall in London offers free guided tours of surprising frequency throughout the week. My Opera in Focus class at the City Lit was obliged to take the building up on this offer as we've been studying Zauberflöte for the past six weeks - and our classroom in Keeley Street backs on to the grand edifice. Indeed, in the early days of the move to our new quarters, eggs were thrown from the Freemasons' Hall onto the windows of a very active music class. Truth, not myth.

We had an excellent guide, even if he fended off some of our more detailed questions. I didn't get much back from asking about the application of the rule of three, which is so important throughout the opera and which dominates the hierarchy of the path to enlightenment, another aspect of Freemasonry which I find rather offputting (the hierarchy, not the enlightenment). Our guide, to my surprise, positively encouraged photos, so they punctuate this entry.

The present building, inside and out, is a monumental tribute to Art Deco, if such a paradox is possible. It was built between 1927 and 1933 to the designs of H. V. Ashley and F. Winton Ashley as headquarters for the United Grand Lodge, itself formed in 1717 (two other lodges previously stood on the site, depicted above). Starting at the superbly laid out, very substantial library and museum, which we were able to browse at our leisure after the tour, we passed through a portrait gallery of notable Grand Masters, including Edward VII looking very splendid in his regalia, and the current incumbent, the Duke of Kent (after whom, it seems, no royals will take up the gauntlet). George IV's especially large masonic throne dominates the room.

Thence down a long processional corridor famous for its use in that engrossing if hokumy BBC series Spooks (the outside of the building will be especially familiar to fans) and recently hired out for the Muppets (!). Its panels are fashioned from a now-extinct mahogany.

Two vestibules to the Grand Temple include a splendid symmetrical set of creation windows.

God is known here as the Great Architect - hence the compasses - to unite all religions; the only qualification for aspiring to join the brotherhood (or sisterhood if you apply to the handful of female or mixed lodges in the UK) is belief in a higher power. Freemasonry is by no means incompatible with any religious practice, merely a moral and practical-living adjunct to it. Lodges around the world use as their Volume of Sacred Law that of whichever happens to be the prevailing religion - so, the Bible, the Koran, the Vedas and so on. At the end of the vestibules is the war memorial by Walter Gilbert, a bronze casket with gold figures, shaped like a barque representing the ultimate journey, more fine stained glass work commemorating the fallen of the Great War.

Massive bronze doors, again designed by Gilbert, open at the touch of a finger. The knocker makes an awe-inspiring sound and could summon masons from any part of the vast building. Gilbert's symbology here is essential to Freemasonry's central allegory of Solomon's temple-building in Jerusalem, a triumph of teamwork between Jews and Phoenicians (none of this in Mozart; and nothing of the Isis-Osiris analogies in the Hall, that I saw, at any rate; though Osiris's death and rebirth are analogous to the ritual of master mason Hiram Abiff in the biblical borrowing). I took this detail from the hall side of the doors, because it marries the wartime preoccupations of Kenneth Branagh's filmed Flute - more anon - with the symbol of silence (hands to lips), sacrifice and (not depicted) wisdom (man holding serpent), prudence, work, loyalty and hope.

I've  been inside the Grand Temple before, for a performance of The Gondoliers featuring our now holy friend Father Andrew Hammond as Don Alhambra del Bolero (inquisitionally prophetic?). I don't think I spent much time then taking in the deco mosaics around the starry ceiling. At the east end above the three master chairs Ionic columns - the two columns of Solomon's temple are always crucial - flank Jacob's Ladder, the symbols of Faith, Hope and Love. Solomon stands on the left, King Hiram of Phoenicia, the temple builder, to the right. For some reason I didn't catch this one, but here are the chairs.

There's a fine organ above them on the north apse wall.

At the west end, the most Flute-y design has Doric columns, Euclid, his 47th problem - the symbol carried by an ex Lodge Master - and Pythagoras. The moon above is surrounded with the wisdom-embodying serpent again (wonder why Tamino has to slay one at the start of the opera).

To the south, Corinthian columns are flanked by an alarmingly Phaeton-like Elijah heading heavenwards in his chariot; above are the all-seeing eye and the five-sided star (many masonic symbols are pentacles, sometimes interlaced triangles).

To the north are composite columns and within them a bit of more mundane heraldry: the arms of the Duke of Connaught and Strathearn. St George and the Dragon are on either side. Celestial and earthly globes surmount the pillars; beneath them are two blocks of stone, unfashioned and fashioned to represent the stages of aspiring to Freemasonry.

The museum has thousands of precious artefacts including attractive 18th and 19th century pottery covered in masonic symbols, masters' thrones, representations of Solomon's temple and reams of banners. This one's interesting in showing the merger of Antients and Moderns; I'm curious that one of them has the symbols of the Evangelists.

I didn't photograph in the museum other than to ask special permission just to snap this 18th century floorcloth as our Sophie is, of course, one of the world's leading specialists in the pre-lino art, and this must be one of the earlier specimens.

We come to the end of our City Lit Flute journey on Monday, after a glorious time floating even more than I can remember on the miraculous cloud of Mozart's incessant inspiration. How wonderful it has been to revisit the great recordings - Marriner with Kiri and Araiza, Mackerras, Beecham, the second Solti which I have now come to love especially for Ruth Ziesak's Pamina - and to watch scenes from three different productions on DVD: Glyndebourne 1978 for Hockney's designs, the core Bergman film which remains for me the best of all cinematic opera and a wary step towards Kenneth Branagh's 2006 fantasy.

It turned out to be highly imaginative, not always tallying with the musical vision - surely the opening scenes on the battlefield are too grim for the initial lightness of touch - but always full of bright ideas and respect for the full score. Joseph Kaiser is such a handsome and vocally excellent Tamino; apparently Branagh discovered him singing the First Armed Man when he went to see René Pape in an American production. Here's Kaiser as Tamino with the Papageno of  Benjamin Jay Davis on the left.

While Davis doesn't make a huge impression and Amy Carson's Pamina is utterly wet and weedy - not at all the trial-leader heroine Mozart and Schikaneder made her become - Pape is a total star. You just have to not mind the thickly accented English (the work is sung in Stephen Fry's not wholly successful translation and his adaptation of very limited dialogue). This is as good a Sarastro as we'll ever hear or see, matching even mighty Kurt Moll for evenness throughout the range, and youthful-natural to boot. The orchestral playing - European Chamber Orchestra under a pragmatic James Conlon - is superb. The still is of Pape with Thomas Randle's against-the-grain Monostatos - and no, the master doesn't have the servant bastinadoed but simply demotes him.

As I hinted above, Branagh's fantasy recreation of a trenches/field hospital scenario may well have taken its cue from the Freemasons' Hall memorial. It mostly works, especially for the trials of fire and water. But again Bergman is unsurpassably moving in this sequence*. The only image of that I could find is on the Criterion DVD cover which I used when I was discussing the 'making of...' film - though amazingly the whole movie is up in quite a good print on YouTube here.

The difference between the two film styles - and it's great that they are so different - is that Bergman, as a theatre director, always values the close-up on the human face, while Branagh succumbs to more recent filmic restlessness by swamping his characters with landscapes, action and the occasional bit of large-scale CGI. But if that brings in a new audience, great. And it's about to open in America, where apparently it hasn't ever been on general release. I'm so glad I didn't write it off unseen. To conclude where we began, here's the great Pape in our lead aria auf Deutsch at the Metropolitan Opera in 1996.

*Having just wound up the opera today (18/1), before looking forward to offshoots in Goethe, Strauss and Hofmannsthal's Die Frau ohne Schatten and Tippett's The Midsummer Marriage, I found myself choked with tears from the last Bergman sequence (we ran the best of all Papageno-Papagena courtships and the proper final scenes together, though Bergman turns the Act 2 finale upside down with some pretty strange reordering). For me, it's still the most bewitching and happy opera film ever made.