The Home Office has apologised to an innocent man after falsely accusing him of being a convicted drug dealer and threatening him with detention and deportation.

The apology was issued after the Guardian began to investigate the case of Antonio Neville Heslop, 56, from Jamaica, who lost everything including his home, job and relationship while trying to apply for a biometric residence permit last year.

He applied for the new permit to replace his old immigration status documents – the Home Office granted him indefinite leave to remain in 2003, the year after he arrived in the UK. He has four British children.

Heslop experienced a significant delay in getting his documents processed. While the Home Office had his immigration status document in its possession he was no longer able to work because he could not prove he was in the UK legally and ended up losing his home. Previously he was earning about £700 a week from his job in the construction industry.

He has no criminal convictions and has worked as a builder, handyman and cleaner since his arrival in the UK, paying his taxes and national insurance contributions.

While the Home Office delay in processing his immigration documents had a devastating impact on him, things took a turn for the worse in March of this year.

Heslop was shocked to receive a letter from the Home Office’s criminal casework directorate saying it was planning to deport him, that he was liable to be detained and had no right of appeal. The letter informed him that all this was happening because on 5 February 2010 he was sentenced to four years’ imprisonment for eight counts of supplying and production of drugs.

The letter states: “You may now be detained. This is because you are a foreign criminal. There is no right of appeal against this decision.”

Heslop has no convictions and was able to tell the Guardian the places where he had been working at the time that the Home Office said he had received the four-year prison sentence.

“I was heartbroken when I received the letter from the Home Office saying they were going to deport me,” said Heslop. “I am so stressed and depressed because of what the Home Office has done to me.

“I can no longer help to support my youngest child, who is 14. My landlord chucked me out. I’m scared to go outside in case I get arrested and put in detention. I’m even frightened to go and see my GP although I feel very bad, in case seeing the doctor leads to me being detained and deported.

“I came to this country legally, I’ve always worked here legally and have paid my tax and national insurance. I never sit down like a lazy person. Some days I feel that I’m only surviving by praying. The Home Office needs to do things better. They have taken away my life. Although I’m still alive I feel as if I’m dead.”

A Home Office spokesperson said: “We can confirm that an individual using the full name and date of birth of Antonio Neville Heslop was convicted of drug offences in 2010. However, an investigation has revealed that this was not Mr Heslop and the individual convicted was using a false identity. We apologise and are now in touch with Mr Heslop’s representatives to assist him.”

Heslop welcomed the apology but raised concerns about the apparent theft of his identity.

“When I got the letter saying the Home Office was going to deport me I kept saying over and over again: ‘What is this? I’m not a drug dealer. I’m a working person and all I want is to get back to work again. I hope that now I’ll be able to do that.”

It is unclear how the person convicted of drug offences, who according to the Home Office used Heslop’s identity, was able to move through the entire criminal justice process using this false identity. Heslop’s solicitor, Naga Kandiah of MTC Solicitors, confirmed his client had no criminal convictions after requesting a disclosure of his police national computer record.

Kandiah said: “The Home Office were planning to deport an innocent man. They have put him and his British children through a lot of anguish. They need to realise they are playing with people’s lives and should not act in this way.”