I think the first time I asked for the opportunity to do an "access" documentary‎ in a prime minister's office was during the Pierre Trudeau era.

There was little discussion. The answer was no.

I've renewed that request in various forms with almost every one of the sev‎en prime ministers who followed Trudeau the Elder.

Until this week, the answer has always been the same: "Not right now."

From 2006 to this year, I tried with Stephen Harper's people, more times than with any previous prime minister. They would always string me along for a while before finally echoing their predecessors: "Not right now."

Prime Minister Justin Trudeau listens to his staff during a meeting in his office. (CBC News)

Access docs mean just that: let us see how the sausage is made. "We'll be flies on the wall," we'd promise. We'd try to stay out of everyone's way and just record events as they happened.

Now, there is a danger in getting a "Sure, let's do it" answer. The access you might get could be stilted or outright phoney.

We've been the subject ourselves of the same kind of requests. Newspaper television critics occasionally ask to sit in on a day at The National to watch everything that happens.

On the one hand, it gives us a chance to show what really happens in a network newsroom operation to some people who write columns clearly from a perspective of having zero sense of what happens.

On the other hand, you risk something untoward happening, a silly comment, let's say, that suddenly becomes the focus of the "behind the scenes story."

The same weighing of risk and reward almost certainly occurs inside any Prime Minister's Office when the "access" request lands on the desk of the director of communications.

Which brings us to this week.

From 'no' to 'go'

I had been trying hard since election night to get "inside" the new PMO as it went through transition from contender to government. No immediate "yes" or "no," which was a good sign, but time was running out.

I much preferred the idea of "access" to the "formal interview" option, which other networks had already done since election day. So, I tried something different. I played the "you talk of openness and transparency‎, so prove it" card.

Peter Mansbridge rides along with Justin Trudeau and his newly sworn-in cabinet in a bus back to the Hill 1:48

That actually seemed to curry some favour, at least with some in the inner Trudeau circle. When the person they call "the Boss" signed off, it was a "go" earlier this week, and away we went.

Some basic agreements were made.

Justin Trudeau would wear a wireless microphone for almost every step of the day on Nov. 4.

We were restricted, simply for space and security, to myself, one camera operator (Jean-François Bisson) and one lead producer (Lara Chatterjee). One camera meant there were going to be some shaky moments,‎ but we had hoped to cover those with shots we would take with our smartphones.

Sadly, in the last-minute edit, there were system issues in the edit suite and the smartphone footage couldn't be used. For most viewers, though, that didn't seem to matter; in fact, it actually gave us what we wanted: a cinema verité feel.

Improvisation – and an infraction

One challenge we had was the scene in the prime minister's bullet-proof limousine — it would only hold four people, two security personnel plus the PM and myself. No spot for Jean-François. In his place, we took a gamble — the RCMP allowed us to temporarily install a mini, fixed, portable camera. It wasn't ideal, but it worked.

Peter Mansbridge rides with Trudeau in the back of the PM's limo 6:41

We put a regular camera in the trunk just to record the sound off the wireless mics we were both wearing in the back seat. It worked.

We both did something wrong, illegal actually, while sitting in the back seat. I'm not sure why it happened, but it doesn't matter, there was no excuse. We forgot to buckle up. Our bad, for sure.

In the end, we got an overwhelmingly positive response, including from many of our competitors. Viewers loved the sense of access, even though it was for the most part a ceremonial day. What they liked is that they were seeing things they'd never seen before.

Does it signal that the new government will truly be open and transparent moving forward? It's a large ask. Prime Minister Trudeau says he believes it's the right thing to do. As we say in politics, time will tell.