|10 Downing Street: the world's most famous front door
So far, so unremarkable. But that meant going through the world's most famous front door - at 10 Downing Street.
Seeing inside No. 10 was a fascinating experience - and after my meeting, I was lucky enough to have a brief "tour".
The only other building I have been inside that gave me such a palpable sense of history was the Pantheon in Rome (which everyone must visit once in their lifetime). Downing Street is much newer and nothing special architecturally - a cluster of Georgian town houses knocked together - but it has been the epicentre of politics in Britain and our Empire for 275 years (and now a workplace for some 200 people).
It was humbling to walk up that famous staircase, lined with the portrait of every former Prime Minister from Robert Walpole to Gordon Brown - and to see a worn and modest brown leather tub chair that didn't look anything, until you heard it was the "smoking chair" used by Winston Churchill.
And I discovered a "secret" that I can reveal exclusively here: have you ever seen that door opening (inwards, uniquely for a front door) as someone approaches it, and wondered how? I asked the security man inside the door how he knows when to open it - and he showed me. To the left of the door on the inside, is a piece of mahogany furniture - but it has a glass top with a TV screen inside, showing four views of the street outside. Walk up to the door, and it opens for you - if you have got through the security on the gates...
The door, by the way, is now (since the 1991 IRA attack on No. 10) a bomb-proof metal one; the original oak door can be seen in the nearby Churchill Museum at the old Cabinet War Rooms.
On walking through that door as the new Prime Minister on 7th May 1940, the day Germany invaded Belgium, Holland and Luxembourg, Churchill said "I felt as if I were walking with destiny, and that all my past life had been but a preparation for this hour, and this trial".
What an experience to follow in the footsteps of history.