Question to the Home Office:

To ask the Secretary of State for the Home Department, how many asylum seekers who arrived in the UK claiming to be under the age of 18 and who were subsequently assessed as being over the age of 18 have since been deported in the last three years.

The Home Office publish the number of age dispute cases raised and resolved for asylum claimants in the Immigration Statistics release each quarter, in table 10 q:

https://www.gov.uk/government/uploads/system/uploads/attachment_data/file/572377/asylum3-q3-2016-tables.ods

In addition, the number of individuals who were returned in each quarter who had previously lodged an asylum claim is published in table rt 02 q:

https://www.gov.uk/government/uploads/system/uploads/attachment_data/file/572379/returns1-q3-2016-tables.ods