Real ale renaissance

In the cramped kitchen of an east London bar and restaurant, Logan Plant is brewing.

He holds a tube in both hands, from which hot water is pouring into a stainless steel grain-filled vat and there is a sweet smell in the air.

"We've blown a few things up," he quips. "There have been a lot of angry chefs."

You may have heard of his dad - Led Zeppelin frontman Robert Plant. 

Here's the story behind a surge in London brewery numbers.