Boris has launched his "Pocket Parks Initiative".

Here's the prospectus.

In summary:

• grants of up to £50K
• funding round 1 open now (open to boroughs)
• funding round 2 open spring (open to community groups)

As a Hackney noob, I'm not really up on local spaces,
but I'm happy to contribute my experience greening Lambeth and some effort...

Regards,
Dave.