As a teacher, you don't normally go to Ofsted. Instead, it has this alarming habit of coming to you. And let's face it, it doesn't wait for an invitation. Like the secret policeman's dawn call, it comes when it decide to - and on its own terms. For my visit to the inspectors, however, there was a period of delicate negotiation before I was allowed over the threshold of their London HQ.
Most teachers have a picture in their mind as to what Ofsted's home turf must look like. The dark heart of Mordor might cover it. Or Moscow's Lubyanka Jail. Or Room 101. Certainly there should be dark clouds overhead; bats circling; shuttered windows and doors; shrieks and lamentations in the air around.
Against such expectations, the inspectorate's eight-storey building on London's Kingsway is something of a disappointment. It's upright, staid and anonymous. If it wasn't for the brass plaque on the door, you could easily walk past.
I arrive bang on time. Any teacher knows that Ofsted will expect to see lateness challenged. My visit begins with a quick tour. It's smart.
Luxurious even. The eight floors of offices rise up on each side of a courtyard. Glass-walled lifts glide effortlessly up and down. All the floors look uncannily alike with well-groomed carpets, islands of swanky desks and state-of-the-art computers - each with its own flat-screen monitor - that clearly come as standard.
As the Ofstedlings go about their devilish work, there is an air of calm industry. To the naked eye, they look almost like humans. No one cackles or chuckles. But maybe all this serenity is something of a veneer. A survey last year indicated high levels of stress amongst Ofsted employees, with two out of three saying they felt unable to speak freely or share ideas.
One in five reported having been bullied or harassed in the recent past.
None of this is alluded to as I meet some of those responsible for running the part of Ofsted which deals with colleges. This has the very un-sexy name of the post-compulsory education division - otherwise known as PCED.
Christine Steadman is the acting head of PCED and she certainly looks the part. In her days before inspecting, she was the principal of a college.
Somehow she has the air of someone who could never have been anything less.
In point of fact, she tells me later, she once taught English in a comprehensive.
Christine leads a team of inspectors whose numbers have doubled to 60 as her remit within Ofsted has grown. I idly wonder what the collective noun is for inspectors: a scourge perhaps, or a lambasting.
She tells me that the team, which already works largely from home, is soon to be scattered far and wide across the country to get "back-to-the-grass-roots". What she actually says is: "The operational delivery of inspection activity will be put into the regions as part of a regional matrix", which, I'm sure, is the way they train all those calm and industrious Ofstedlings to express themselves too.
The move is part of a much wider restructuring of Ofsted's activity which is due to happen in September. The idea is for inspectors to get closer to all involved in post-16 education - employers as well as providers such as colleges. This new structure is designed not only to trim back Ofsted's Pounds 200 million budget, but also to improve the inspectorate's local intelligence. Or, put another way, to help them learn what is really going on out there.
Christine's colleague, Angela Cross-Durrant, who heads up policy and planning in PCED, tells me about some of the other changes in the pipeline.
Just as Ofsted encourages "differentiation" in the classroom, so will they themselves now differentiate between those seen to be doing well on the one hand, and the basket cases on the other. Whether the latter are to be known as the NGs (national disgraces) is something we don't discuss. What it will mean is that the good boys will get a light-touch inspection, while only the potential NGs will be hit with the full works.
The other big change coming up in September is the cutting of the period of notice from the current three months to three weeks. This is a theme taken up by the third PCED luminary I meet, Rhys Evans - who tells me with a disarming smile that even three weeks is too long as far as he's concerned.
"If we could get down to no notice, we'd be very happy."
Rhys assures me, however, that this desire to cut back on the notice period comes from the best of motives. To this end, he points out what every lecturer knows: that prior to inspection colleges are crawling with highly paid consultants, clutching bottles of their own-brand "drink-me-and-shine-in-inspection" elixir. "Vast sums are being spent on consultants," he says, "money that should be spent on front-line resources."
I decide to raise one final point with Christine and Angela: the negative perception of Ofsted that prevails in many colleges. Up till now, they have both been very nice to me. They continue to be very nice. Nice, but defensive.
"We are aware of the impact we have when we go into colleges," says Christine.
"No one would thank us if we weren't doing a proper job," says Angela.
"At the Association of Colleges conference, the principals were very supportive," says Christine.
"We get letters of thanks from individuals in colleges," says Angela.
Letters of thanks? I query. "Yes," says Angela, "and letters of appreciation from teachers, principals and students."
I leave reflecting on this, and what such a letter might look like. Perhaps principals of failing colleges really are contrite. Perhaps, like good children after Christmas, they really do sit down and write thank-you letters:
"Dear Mr Bell, Thank you for pointing out all the inadequacies of my college. Your comments were all merited, and I truly do deserve the label national disgrace. Keep up the good work.
"PS. Where do you keep the bats?"