Objections related to climbers’ safety, hazards to those crossing the bridge below and the possibility of damage to the 1,600-ft span, an international heritage site. But one by one these obstructions were countered or accommodated, and the result is not just an exhilarating ascent; it is a lesson in ingenuity and enthusiasm.

Climbers are not allowed to carry anything on to the bridge - not even a wristwatch - in case it falls on to the traffic below or the tourist-thronged harbourside.

Spectacles are secured to the special one-piece nylon jumpsuit which everyone wears. This is coloured so as to help camouflage you against the bridge and zips up at the back to prevent you getting at anything you did sneak into your pockets.

To ensure no one falls off, a continuous safety wire runs the whole length of the climb, cunningly attached to ensure it has no permanent effect on the bridge fabric. In groups of half a dozen, climbers are harnessed to this endless cable. Whether it is just to ensure we get this right or to put a bit of steel into our own nerves, we first practise the procedures for hooking-on on a bridge simulator, which is duly shaken to reproduce the effect of trains. Meanwhile Julie, our climb leader, introduces us to the earpieces through which she will keep up a stream of hearty encouragement during the two-hour traverse.

Julie is a strapping young Tasmanian oozing confidence and enthusiasm. Suitably innoculated with some of this, we are soon clipping on and making our way along the narrow catwalk slung 100 feet or so beneath the bridge approaches. A steep climb up a steel ladder takes us up beyond the pair of granite towers which decorate each end of the bridge. From here we begin what in all honesty is the fairly gentle slope of the main arch (my native South Downs are much steeper) to the flagpole at the summit.

Here the irrepressible Julie produces a digital camera and takes individual pictures carefully framed to include the nearby Opera House. And do we have any questions?

By this time Julie has told us just about everything we might want to know about the epic construction (built between 1923 and 1932), held a quiz about the number of rivets and marvelled at the whole half-day’s holiday declared when the two halves of the arch first met in the middle (only in fact to part again that night when they cooled down and the bridge contracted).

Australians are unashamedly proud of their country and achievements. The national pride is evident in their enthusiastic celebration of Australia Day, support for their sporting teams and the way they honour their fallen and veteran armed forces, including those who served in Vietnam. In return, however, they do not appreciate our more self-deprecating style which they see as “running down yer country”. And I discover that the top of Sydney Harbour Bridge is not the place to ask where all the steel came from. “Here we go...” mutters the otherwise ever-cheerful Julie. The words “whingeing” and “Pom” hang unspoken in the wind.

Apparently, the steel was all shipped out from Britain. And (purely for the factual record, you understand) after an international competition the design chosen for the bridge was one modelled on the steel arch spanning the Tyne in Newcastle.

The view from the top ... well, given that this is a bridge, the view from the top is mostly of water. And not just of that lying in the harbour, because wending its way in from the sea, through the famous Heads at the harbour entrance, is a squall. And like our hapless cricketers, I am soon saved from any further onslaught from the enthusiastic Tasmanian by the rain. We struggle into cagoules, which is a bit awkward since like everything else we carry they are already firmly attached to us.

Squelching back to base, we fill in our evaluations of the climb and its leader. I write on mine, (and not just because I have a thing about dominant women): “Outstanding leader. I’d follow that Julie anywhere.” And I would.