The Home Office has become embroiled in an embarrassing row over its controversial immigration programme after it emerged text messages targeting suspected illegal migrants had been sent to British nationals by mistake.

A total of 39,100 text messages have been sent by private firm Capita on behalf of the government as part of a contract to track down individuals who may not have the right to live in Britain.

The text message reads: "Message from the Home Office. Our records show that you may not have leave to remain in the UK. Please contact us on 0844 3754636 to discuss your case."

Labour shadow immigration minister David Hanson MP said: "These messages will rightly cause distress and offence to British citizens, many of whom have done much to contribute to our society.

"It is simply wrong for this sort of message to be sent by text, and to be so poorly targeted."

A Home Office spokesman said: "We are taking proactive steps to contact individuals who records show have no valid right to be in the UK, some of which date back to December 2008. We believe it is right to enforce the immigration rules.

"Out of thousands of people contacted by Capita, a small number have been found to have the right to be in the UK or have an outstanding application. Anyone contacted in error has been asked to get in touch with Capita to update their records."