From the AES website (AES Annual Exhibition 2010):
"Celebrate the 75th anniversary of the the Amateur Entomologists' Society at our annual Annual Exhibition and Trade Fair.
This is the entomology show to attend. The show takes place at Kempton Park Racecourse near London and exhibitors and traders pack two floors of exhibition space.
The exhibition is open to members of the public and not just members of the AES. Should you wish to join the AES then you can do so on the day but you don't have to be a member to attend. Ticket prices are yet to be confirmed but are likely to be similar to the 2009 prices: £3 per adult and £1 per child. Tickets can be bought on the gate.
Traders include those selling books, equipment, livestock, specimens and food plants. In addition, the show is attended by most of the major invertebrate societies and organisations within the UK."
This is the best UK insect show for the general entomologist, and there will be lots of people selling live and dead specimens, equipment, books, etc. I plan to be there, and will probably be found at the Phasmid Study Group table.