UK Border Agency
As of the 1st of April 2013 what was the UK Border Agency has now become two units within the Home Office. 

Freedom of Information Requests should therefore be directed to the successor body: The Home Office.  

For more information see the Home Secretary' statement to the commons on the 26 of March 2013 on the abolition of the UK Border Agency

The former UK Border Agency website states:
"On 1 April 2013 the UK Border Agency was split into two separate units within the Home Office: a visa and immigration service and an immigration law enforcement division"

Enquiries relating to individual immigration and nationality cases must not be made via WhatDoTheyKnow. To get in touch with the UKBA directly please click here for direct contact information for the UKBA.

The UK Border Agency formed in April 2008 as a merger of the Border and Immigration Agency (BIA), UKVisas and the port of entry functions of HM Revenue and Customs (HMRC).

The UKBA replaced what used to be called the Immigration and Nationality Directorate (IND).

The full text, including the email addresses, provided by the UKBA in their standard FAQ reply to some requests is available at: here.