Brussels has sounded the alarm at a fresh threat to EU citizens living in the UK after Brexit, as the Commission’s president arrives in London for talks with Boris Johnson.

The prime minister is under fire over sudden plans to “water down” an independent watchdog meant to protect citizens’ rights during the exit process.

The independent monitoring authority (IMA) was stipulated in the Brexit agreement, but under the UK’s planned implementation of the deal its powers will be split up and cannibalised by other bodies.

A letter sent by Michel Barnier, the EU’s Brexit negotiator, raises “concern” that EU citizens may not have a fully-independent organisation through which to make complaints against the government – amid a backdrop of serious distrust between EU citizens and the British state.

The EU’s chief negotiator warned that the IMA must have the ability “to act rapidly and in full independence” on any problems raised, adding that a number of “issues of concern” had already emerged about the settlement scheme.

Bizarre: Boris Johnson drives 'Brexit' digger through boxes Show all 8 1 /8 Bizarre: Boris Johnson drives 'Brexit' digger through boxes Bizarre: Boris Johnson drives 'Brexit' digger through boxes Conservative party leader Boris Johnson drives a JCB through a fake wall POOL/AFP via Getty Images Bizarre: Boris Johnson drives 'Brexit' digger through boxes Prime Minister Boris Johnson during a visit to JCB cab manufacturing centre in Uttoxeter, while on the General Election campaign trail. PA Photo. Picture date: Tuesday December 10, 2019. See PA story POLITICS Election. Photo credit should read: Stefan Rousseau/PA Wire Stefan Rousseau PA Bizarre: Boris Johnson drives 'Brexit' digger through boxes Britain's Prime Minister and Conservative party leader Boris Johnson drives a Union flag-themed JCB, with the words "Get Brexit Done" inside the digger bucket, through a fake wall emblazoned with the word "GRIDLOCK", during a general election campaign event at JCB construction company in Uttoxeter, Staffordshire, on December 10, 2019. - Britain will go to the polls on December 12, 2019 to vote in a pre-Christmas general election. (Photo by Ben STANSALL / POOL / AFP) (Photo by BEN STANSALL/POOL/AFP via Getty Images) BEN STANSALL AFP via Getty Bizarre: Boris Johnson drives 'Brexit' digger through boxes Prime Minister Boris Johnson sits in a cab of a JCB during a visit to its cab manufacturing centre in Uttoxeter, while on the General Election campaign trail. PA Photo. Picture date: Tuesday December 10, 2019. See PA story POLITICS Election. Photo credit should read: Stefan Rousseau/PA Wire Stefan Rousseau PA Bizarre: Boris Johnson drives 'Brexit' digger through boxes Britain's Prime Minister and Conservative leader Boris Johnson drives a Union flag-themed JCB, with the words "Get Brexit Done" inside the digger bucket, through a fake wall emblazoned with the word "GRIDLOCK", during a general election campaign event at JCB construction company in Uttoxeter, Britain, December 10, 2019. Ben Stansall/AFP/Pool via REUTERS POOL REUTERS Bizarre: Boris Johnson drives 'Brexit' digger through boxes A sign made for a visit by Prime Minister Boris Johnson to the JCB cab manufacturing centre in Uttoxeter, while on the General Election campaign trail. PA Photo. Picture date: Tuesday December 10, 2019. See PA story POLITICS Election. Photo credit should read: Stefan Rousseau/PA Wire Stefan Rousseau PA Bizarre: Boris Johnson drives 'Brexit' digger through boxes Britain's Prime Minister and Conservative party leader Boris Johnson drives a Union flag-themed JCB, with the words "Get Brexit Done" inside the digger bucket, through a fake wall emblazoned with the word "GRIDLOCK", during a general election campaign event at JCB construction company in Uttoxeter, Staffordshire, on December 10, 2019. - Britain will go to the polls on December 12, 2019 to vote in a pre-Christmas general election. (Photo by Ben STANSALL / POOL / AFP) (Photo by BEN STANSALL/POOL/AFP via Getty Images) BEN STANSALL AFP via Getty Bizarre: Boris Johnson drives 'Brexit' digger through boxes Britain's Prime Minister and Conservative party leader Boris Johnson reacts as he sits in the cab of a drives a Union flag-themed JCB, after driving through a fake wall emblazoned with the word "GRIDLOCK", during a general election campaign event at JCB construction company in Uttoxeter, Staffordshire, on December 10, 2019. - Britain will go to the polls on December 12, 2019 to vote in a pre-Christmas general election. (Photo by Ben STANSALL / POOL / AFP) (Photo by BEN STANSALL/POOL/AFP via Getty Images) BEN STANSALL AFP via Getty

The 3.2m EU residents in the UK are already highly-suspicious of the ‘settled status’ scheme meant to guarantee their status after Brexit, warning some rights will be lost.

Brandon Lewis, the security minister, heightened those fears when he appeared to threaten EU citizens with deportation if they do not apply for settled status before the deadline of 30 June 2021.

It is believed that both the Home Office and the Brexit department opposed the power to abolish the IMA – but were overruled by No 10.

The fresh row comes ahead of Mr Johnson’s first meeting with Ursula von der Leyen, the European Commission president, in Downing Street later today.

The pair are already on a collision course over the demand for a trade deal to be secured by the end of the year, even as the UK seeks to break free from EU regulations.

The trade talks risk being soured over Brussels’ renewed fears over Britain’s commitment to the rights of EU citizens once the transition period ends.

The European Parliament has echoed those concerns in a separate resolution drafted by the main political groups and due to be backed by MEPs next week.

MEPs fear that, without a “physical document” offering proof of right to residency, there is an increased “risk of discrimination” by prospective employers or landlords, who may want to avoid the burden of online verification.

The lack of assistance offered to “older and vulnerable” EU citizens, including those who may have difficulty in using digital applications, will also be criticised.

The European Parliament’s Brexit coordinator Guy Verhofstadt has previously encouraged MEPs to reject the deal if problems with citizens’ rights were not fixed by the UK, though in practice they are very likely to approve it. The parliament is scheduled vote on the withdrawal agreement on 29 January at an extraordinary sitting in Brussels.

But Stephen Barclay, the Brexit secretary, has dismissed the concerns over EU citizens’ treatment, insisting he had been able to “reassure” Mr Barnier after receiving his letter.

He insisted the UK “hugely valued” EU citizens, adding: “We want them to stay and the [withdrawal agreement] bill delivers on that.”

The minister also added: “Many of the issues you have raised in your letter will apply equally to UK nationals in the EU and I note that some member states are still to set out details on what UK nationals will be required to do to protect their rights.”

But Liberal Democrat MEP Caroline Voaden warned: ”By watering down the role of the Independent Monitoring Authority, agreed with the EU to monitor the rights of EU citizens in the UK, Boris Johnson is risking a new Windrush scandal.