Tech companies help the homeless

American cities are no stranger to wealth inequality - but in San Francisco it is rising faster than any other.

Seduced by record levels of employment and investment, tech companies and workers have been flooding to the area.

But as its complexion has changed, long-time residents bemoan what they see as the gentrification of the city - with accusations the new arrivals are not doing enough to support the city they now dominate.

The BBC's North America technology correspondent Richard Taylor has been on the road to witness how it has been playing out.