The Home Office has drawn up a secret programme using homelessness charities to acquire sensitive personal data that could result in the deportation of non-UK rough sleepers, the Observer can reveal.

A chain of emails from senior Home Office officials from December 2018 to May 2019 also shows that the clandestine programme ignores European privacy laws by passing rough sleepers’ sensitive personal information directly to the Home Office without their consent.

The scheme, which is still in a trial phase, is seen by charities and campaigners as the latest manifestation of the Home Office’s much maligned “hostile environment” policy. A previous plan to deport EU rough sleepers was defeated 18 months ago when the high court deemed it unlawful and discriminatory.

But the Home Office, apparently undeterred, has rolled out a remarkably similar new scheme which, according to an internal email, will lead to “enforcement in some cases” – deportation – and targets “non-UK” and non-EEA (European Economic Area) rough sleepers, which after Brexit will include EU nationals.

Gracie Bradley, policy and campaigns manager for the human rights charity Liberty, said: “It’s disgraceful that the Home Office, local authorities, and charities are attempting to turn trusted homelessness outreach workers into border guards. Homelessness charities must refuse complicity in the hostile environment.”

A spokesman for the Public Interest Law Centre, which won the high court case, said: “It’s now clear the Home Office – with the Greater London Authority, local councils and some homelessness charities – is trying to resurrect this discriminatory policy under a different guise.”

The Home Office is trying to resurrect this discriminatory policy under a different guise Public Interest Law Centre

The correspondence reveals that some refugee charities have already been asked to forward cases to the programme, called the Rough Sleeper Support Service (RSSS), and at least one has agreed. Emails also reveal that homeless charity St Mungo’s has attended meetings with the Home Office to discuss allowing outreach workers to enter a homeless person’s data into RSSS without their consent.

An email, dated 10 April 2019 from a Home Office official, confirmed the scheme “provides a single point of contact for LAs [local authorities] to receive rapid immigration status checks on non-UK national rough sleepers”. It also explains why it wants to bypass privacy laws: “A system relying on consent to comply with the GDPR [EU General Data Protection Regulation] would be vulnerable to individuals withdrawing consent.”

Another email, dated 18 February 2019 to GLA officials, shows that targeting homeless individuals would be prompt, saying “immigration [status] checks are completed on rough sleepers within 24 hours of a referral”.

Obtained through freedom of information requests from Liberty, the correspondence says the scheme is spearheaded by the lead officer for previous immigration enforcement operations and will be “utilised to resolve the non-EEA national rough sleepers situations”. The emails also chronicle Home Office frustration that the programme is still in the test phase because of a failure to agree a data-sharing deal with charities and local authorities.

The emails show significant opposition from charities with “push back” from several including St Mungo’s and migrants advocacy group Praxis, who warn of “reputational risks” for groups linked to the scheme. According to one email, Praxis raised several concerns, including that the scheme risked “poorly made decisions”, was unnecessary and that it was “unclear if RSSS referral would make detaining and removal of rough sleepers at their reporting appointments more likely”.

The charity raises fears that the programme will be primarily geared at removing rough sleepers. “There appear to be no immigration decision-makers in the RSSS, just immigration officers. The culture embedded in the RSSS seems to be one of enforcement,” it said in an email sent on 3 May 2016.

Even as the scheme was conceived, fears existed that it would be controversial. One email, sent on 18 December 2018, from a GLA officer to the Home Office, cites a “possibility of bad press surrounding the RSSS and there needs to be a clear line on what this team is and how it can help ensure no one dies on the streets”.

Although some emails show that sharing information with the Home Office could help prioritise a person’s case and ensure homelessness charities offered the right support, Bradley said referrals will likely result in immigration enforcement action.

She said ministers should be concentrating on combating the root causes of homelessness rather than targeting rough sleepers. “Consent and data protection should also be at the heart of our interactions with public institutions,” she added.

The Public Law Interest Centre spokesman added: “Despite its name, the new RSSS offers no ‘support’ to homeless migrants living in the UK. It is an ‘hostile environment’ measure in all but name.”

A St Mungo’s spokesperson said the charity had met Home Office staff “to find ways to respond more quickly” to non-UK cases. “In particular, we are seeking to ensure people who may use the service do so based on informed consent and legal advice from a registered immigration adviser,” they added.

A Home Office spokesman said the RSSS was set up “to help resolve the immigration status of non-UK nationals sleeping rough, either granting lawful status or providing documentation. This enables individuals to access support or assists them in leaving the UK where appropriate.” He added: “The service prioritises support work on outstanding cases and helps to resolve status issues.”

A London mayoral spokesperson said: “Heavy-handed enforcement is not the solution to rough sleeping and our services will have no part in it. We have made absolutely clear to the Home Office that we do not support their approach or any other that victimises people sleeping rough.”

The latest homelessness figures show 8,855 people were seen sleeping rough in London during 2018-19, 18% higher than the previous 12 months.