Matt sent me this for Watcher of the Skies
Cycling through Clissold Park in London's Stoke Newington, I heard and then briefly saw a flying parakeet. You can't miss their distinctive bright green colour.
They've been around West London (especially along the wilder bits of the Grand Union Canal, and around Richmond Park) and North West London - Hampstead Heath – for some time now. I remember hearing that the ones in West London were Indian parakeets, and in West London they were Monk's parakeets. I've never seen them in South London, but I'm told they're now abundant round there too - Gypsy Hill, Burgess Park, etc.
My Clissold Park sighting means they're now moving East - while Stoke Newington is an N17 postcode, it's in the London Borough of Hackney, which many Londoners would regard as the start of "East London." It's the first time they've turned up in a N postcode.