Thereafter I ran along the south bank of the Thames to Vauxhall Bridge and back on the north side. I diverted past the Houses of Parliament, pretending I was running in the London Marathon again as I went down Bird Cage Walk and along the Mall, before going along the Strand and retreating along the river bank.
The previous time I had run across Tower Bridge, the day before the London Marathon, I had stopped to talk to a couple of 2 hour and 4 minutes marathon runners! This time I saw dozens of runners and joggers that would take twice that time, or more, to cover the marathon distance and my pace was closer to the latter than the former.
I had the amazing luxury of closed roads in the centre of London as preparations for the Tour of Britain cycle race unfolded - I saw a little of the time trial later in the morning.
30 years ago we could never have imagined so many middle age people running around the towns and cities of the British Isles. But neither could we have imagined the lack of young people doing the same.
Middle to long distance running standards peaked in the early 1980s. Yet, by the time I ran the Great North Run in 1998 I expected to have to go sub 74 minutes just short of my 42nd birthday to be sure of making the top 200. I would say this, but there was a strong head wind year that year and I only managed 75.21 but it was good enough for 140th.
This year's stage managed Great North Run had the poorest standard ever with the 100th finisher much slower than the same position in the very first year when most of the field were locals. My 1998 time would have achieved 57th this year in much better conditions.
There were just 25 runners in the good club runner standard of 70 to 75 minutes.
I'm greedy. I want to keep the slower runners that are so welcome to our sport but I just wish there far more 20 to 35 years old running and committing to some hard training.
In the early afternoon of that Sunday I went walking close to the Olympic Park.
The grandeur of the architecture and facilities is to be admired. But there must be so many young men capable of running under 75 minutes, and women the equivalent standard of sub 83, just by using the parkland, the canal paths and the pavements.
We're told to mind the gap in London and of course the gap doesn't exist on the modern underground lines. But above the surface the gap between the elite runners and the average time has never been more exposed.