See London in a new light, with the streets glowing in neon.

A London full of people walking in the same direction, beating cancer one step at a time.

And yes, a London where people actually say hello as they walk past.

The 20th of September is Cancer Research UK's Shine Nightwalk, and it's when London really sparkles.

Step up and sign up today at shinewark.org.

Choose from the 10K, half marathon or full marathon walk

and get 30% off your entry.

Together we are beating cancer.

Teas and Cs apply.

I always cut through the little park in front of the American Embassy.

Just a little walk through and

cross the road and there's, I think, three or four steps up to the entrance of the Millennium Hotel itself.

This is episode two of Polonium and the Piano Player, a four-part series from Sky News Storycast.

I'm Diana Magne.

At the end of episode one, we left Derek Conlon on the afternoon of November 1st, 2006,

as he was making his way to the five-star Millennium Hotel in Mayfair, London.

At the same time, inside the hotel's piano bar, Alexander Litvinenko, the former Russian agent,

has just picked up a cup of green tea poisoned with the deadly radioactive substance, Polonium 210.

And right now, Alexander is drinking from that cup.

As Alexander sips on this nuclear poison,

the poker-faced Russian agents Lugavoy and Koftoon,

whose barbill includes expensive Cuban cigars and designer gin,

...