Wake at 4am, doze. Breakfast at Lantana, then into work at a little-known (and cared-for, if we're honest) Arup office at Maple House on Tottenham Court Road. My two major corporate employers, in the years in-between start-ups, have been the BBC and Arup, both of whom own or lease large amounts of this area between Tottenham Court Road and Portland Place, bounded by Fitzroy Sq to the north and Oxford St to the south. I know it inside out, or at least I used to. It's interesting, and a little sad, to sense how quickly my mental map of the city is fading through under-use.

I then have to give a lunchtime presentation, in both the No.8 conference rooms, and over the Arup network across the UK, with 10 or so offices joining in via videoconference. I'm discussing, with my colleagues, our series of 'UrbanLife' workshops for the C40 group of cities, and specifically the 'Smart Cities' workshop i helped delver for the City of Melbourne and others last month. Seemed to go well.

Rest of the day spent working on a presentation for Wednesday, from the coffeeshop in the No.8 building. Then out with a different set of mates at the Crown and Sceptre in Fitzrovia. It's always such a blur, these flying visits, such that seeing old friends is both delightful and unsatisfactory.

After a Skype with home, succumb to jet lag at 11, despite having lots of work to do in the evenings this week.

Photos from London, May 2010