Although the transfer window formally opens on 1 July, domestic transfers between clubs in the same association (eg England or Scotland) can take place as soon as a club completes its last competitive 2010/11 fixtures.
Outside of the transfer window, clubs may still sign players on an emergency basis (such as if they have no goalkeepers available) with special dispensation from their competition's governing body, for example the Premier League.
Players who are out-of-contract free agents can be signed outside of the transfer window if they were unattached when the previous window closed, although most leagues have their own deadlines for clubs to register players to play during the season.
All transfers player joining and leaving Premier League Clubs
31st Aug 2011
Joel Campbell [Arsenal - Lorient] Loan Shane Duffy [Everton - Scunthorpe] Loan
Zdenek Grygera [unattached - Fulham] James Hurst [West Brom - Blackpool] Loan Shaun Maloney [Celtic - Wigan] £1m Gilles Sunu [Arsenal - Lorient] Undisclosed
Patrick Van Aanholt [Chelsea - Wigan] Loan