Venues to perform improv in and shows that need improvisers in.

Got an impro show? Here's some places to perform it.
Are an improviser? Here's some more groups/nights that might want you to perform with them.
I don't have all contact details but they should pop up on google.
This is an ever changing fluctuating list so please let me know if I've missed any. 
 
Tuesdays: The Miller, London Bridge. Two different impro groups a night. Programmed by Steve Roe from Hoopla (www.HooplaImpro.com) in association with Jon Monkhouse (www.LondonImprov.co.uk). Next year it will generally be one show that's been directed/produced by Hoopla/Steve combined with one guest group. We're trying to support new shows, with most new shows getting at least one showing at Miller Tuesdays, so there is much variety as possible.
 
Wednesdays: The Miller, London Bridge. Two different groups a night. Programmed by Jon Monkhouse (LondonImprov.co.uk) in association with Hoopla.
 
Thursdays: Grand Theft Impro, The Wheatsheaf, they have guest performers that tend to be from the very experienced section of improvisers.
 
Sundays: Crack Comedy Improv Sundays with two different groups every single Sunday. Programmed by Luisa Omielan (www.iloveluisa.com)
 
Sundays: Wilmington Arms. Every Sunday with experienced Harold Players working together. Might be doing some jams too. http://www.thewilmingtonarms.co.uk. Gareth seems to be coordinating this, sorry don't have his full contact details to hand.  

Every other Thursday: Fingers on Buzzards, The Horse. Sometimes has guest performers, Matt Andrews is the chapt. http://fingersonbuzzards.wordpress.com/
RH and Friends: The RH Experience Shows, with added different performers each time. www.therhexperience.co.uk

Hoopla Friday Night Impro Party: Open to all improv jam, turn up and perform, first Friday of the month, starting this Friday at The Miller.

The Horse - really good venue, free to hire if you're bringing in an audience, lots of impro groups performing ad hoc or regular shows here now. www.horsebar.co.uk
 
The Inflatables - Great short form show that sometimes has guest cast. Andrew Gentilli is your man.

Fat Kitten - don't think they are looking for cast at the moment but it's a crime to talk about impro in London and not mention them. James Ross runs awesome nights with them and other comedy acts including some mega big stuff.

Battle Acts - They do verses shows in Brixton and may be interested in some other teams to play against.

Catch 23 - Cool format directed by Paul Foxcroft that has different teams performing.

The Wheatsheaf, Rathbone Place - cheap to hire, good for ad hoc impro shows but probably won't do more regular shows than GTI.

The Round Table, Leicester Square - really small venue, Hoopla used to perform every Tuesday here, free to hire, right next to Leicester Square Station. Not great for big shows but fun atmospheric place to put on a cheeky test show.

Leicester Square Theatre - massive venue and also smaller cabaret venue. Heard good things about their marketing ability at bringing in their own audience, but heard it can be a bit pricey.

Canal Cafe Theatre, Hen & Chickens, The Pleasance, Camden Etc - haven't really worked with them but they've all had various workshops there.

Crunchy Frog Collective - www.thecrunchyfrogcollective.com - best website for staying up to date with impro casting calls etc.
 
Casting Call Pro - another good casting website. If you're looking to build up acting experience this is a good one.

Hoopla
 
www.HooplaImpro.com