Thank you New York

It’s hard to leave a great city. Even when returning to one that's arguably even better.

This is where I was born. I owe my very existence to the rich mix of people in this intense space who funded what was then the Puerto Rican health scheme. It funded my birth when my student parents would have struggled to get health insurance.

I thank the city for that. I thank the splendid, charming, patient supermen who escorted me around Manhattan over the last few days. In London I travel by bike with one cycling aide. Mike Bloomberg has now allowed me to glimpse that world where an SUV is always waiting, the doors always open, the hassle always pre-empted. It was a real treat. I cannot name the guys (for obvious reasons) but they know who they are and I'm grateful.

Thank you Mayor Bloomberg for the security detail. Thank you too for the wonderful dinner at your home and your kind words at the Manhattan Institute.

We are different political beasts but we have much in common. I salute your success in New York and our time together will sharpen my focus and stiffen my resolve.

I'm still reflecting on the site of ground zero - eight years on - and the tales your team have told me of a rising death toll and fresh suffering.

We share similar challenges safeguarding investment, seeing off threats to our core industries and persuading our most wealthy constituents that they have much to gain by proving their social responsibility.

Our shared privilege is to preside over people who have energy, enterprise and creative genius. We are fortunate and the good people of London and New York should face the future with confidence and determination.

Wrap up from Times Square

More videos from New York are available at www.youtube.com/mayorsofficelondon

Speeches at Columbia University with Mayor Bloomberg

Inspiring session with Michael Bloomberg, gently sparring over the relative strengths of our great cities. Have agreed we’re both high on a list of the two best cities in the world. Shamelessly boasted about London’s advantage in terms of universities, theatres, bookshops, Wi-Fi and a number of other fields. But both cities have a shared edge on the core qualities that lift us - energy, enterprise, creativity and a generosity of spirit. Packed hall at Columbia University where I used to sleep through lectures - not because they were tedious but because I was a baby when my mother was here as a student. Today's seminar proved very lively and spending time with Michael Bloomberg has sharpened my vision and resolve to re-establish London as the greatest city on earth when we welcome the world to our Olympics in 2012.