Aberystwyth
Exploding Fish (Aberystwyth University)

Basingstoke
Basingstoke Improv (part of Nathan Improv)

Bath
Bath Improv

Bedford
At the Drop of a Hat

Birmingham
Birmingham Improv Festival
Box of Frogs
Fat Penguin Improv
Foghorn Improv
Freewheelers
Jumprov
The Improlympians
The Kneejerks
The Ministry of Improv

Bournmouth
ImprovWithUs

Brighton
Blanket Fort
Brighton Improv
Existential Pants
The Hee-Ha's
Impromptyou
John Cremer
Katy and Rach
The MayDays
Musical Improv Comedy
The Noise Next Door
Off the Cuff
Short & Girlie Show
Ten Thousand Million Love Stories
The Twitnits

Bristol
The Bristol Improv Theatre
Bristol Improv (University Society)
Closer Each Day
Degrees of Error
The Idle Playthings
Instant Wit
Nathan Improv Bristol
Space Monkeys
The Unnamed
Watch This Space

Cambridge
Cambridge Impronauts
The Cambridge Improv Factory
Hoopla Improv Cambridge

Canterbury
Impro4
Merlin's Beard (Kent University)

Cardiff
Cardiff Impro (part of Nathan Improv)
Ludus Ludius
Patrick Harries

Cheltenham
Comic Sans Script

Coventry
Wow Impro

Durham
ShellShock! (Durham University)

Edinburgh
ImproFX
The Improverts
To Be Continued
The Impromancers

Exeter
Improperly

Folkstone
Improv Gym

Hampshire
Instant Soop

Lancaster
We Are Improv

Leeds
Comedy Checkout
The White Coats

Leicester
The Same Faces
Unidentified Flying Improv

Liverpool
Impropriety
Improm2
Liverpoool Comedy Improv (with Emma Bird)

London
All Made Up
Alphabetties
Austentatious
BYT Experimental Theatre Group
Battle Acts
Breaking and Entering
C3Something (C3467X)
Cabaret d'Impro
City Impro
The Comedy School
Comedy Store Players
The Cot
Crunchy Frog Collective
Clusterfox
David Shore
Dead Man in a Box
Do Not Adjust Your Stage
Dr. Synistra
Extempore Theatre
Fat Kitten
Fluxx
The Free Association
Friendly Fire
Grand Theft Impro
Hoopla Impro
Improbabble
Improdigies
ImproFest UK
Impro Jam
Imprology
Impro Monkeys
Impromptu Shakespeare
ImproPlay
The Impro Punks
The Improsarios
Improvedy
Improvisation Academy
The Inflatables
Kevin Tomlinson
LAIM
London Improv
The London Jam - (International Improv Festival)
The Magic Mad Hat
Mischief Theatre
Monkey Toast
Multiverse
The Murderettes
Music Box
The Nomadic Academy for Fools
PantherCannon
The Parentheticals
Project Two
Red Lorry Yellow Lorry
The Rubiks
The School of Laughter
The School of Night
School of Playback Theatre UK
Shoot from the Hip
Short and Girlie
Shotgun Impro
Showstopper! The Improvised Musical
Story Kitchen Impro
Sprout
The Spontaneity Shop
Storybag
Third Person Theatre
Upshot Comedy
Upstairs Downton
Very Serious People
West London Improv
Women Who Wank
Yes Ampersand

Manchester
ComedySportz
Improv on Demand

Newcastle
Matt and Ian
Newcastle Improv
On the Spot
The Suggestibles

Northampton
The Same Faces

Norwich
Dogface Improv

Nottingham
Missimp
Student Improv Nottingham

Oxford
Whisky for Breakfast
Awkward Actors
The Oxford Imps (Oxford University)
Racing Minds

Peterborough
You're in Control

Reading
Mad Monkey Improv
What’s The Game?
Free Radicals

Sheffield
The Antics
Shrimps

Southend
Scared Scriptless

Surrey
Non De Script

Associate groups outside the UK
Alan Marriott (Vancouver, Canada)
Crunchy Frog Collective North Shore (Vancouver, Canada)
Patti Stiles (Melbourne, Australia)
The Craic Pack (Dublin)