People crossing the Irish border would have to register in advance to avoid checks and delays after Brexit under a hugely controversial plan being considered by No 10.

Anyone without “fast-track movement” clearance would have to use approved crossing points or would be “considered to have entered the state irregularly”, the study suggests.

Despite Theresa May’s insistence that the border will continue to have no “physical infrastructure”, both CCTV and cameras to track vehicle number plates would be needed at some crossing points, according to the blueprint.

Nevertheless, the Prime Minister has told MPs she has “asked officials to look at it very carefully”, adding: “I believe it gives some very good proposals for solutions.”

The decision to consider the plan, put forward in Brussels, was strongly criticised by the Irish government, which told The Independent the proposals would break Ms May’s pledge of no “physical infrastructure and associated checks” after Brexit.

Peter Hain, the former Northern Ireland Secretary, went further, warning the proposal to pre-register travellers “would be risking immediate civil unrest”.

“If I was Northern Ireland Secretary and this report came on to my desk, its next stop would be the bin,” Mr Hain said.

Donald Tusk on Brexit negotiations: Ireland first

The package of measures has also attracted support from the Democratic Unionist Party (DUP), the Tories’ partners in government, which hailed it “as an excellent foundation to build on”.

“I strongly recommend that all read this – borders, in summary, need to be dragged into the 21st century,” wrote Emma Little-Pengelly, the Belfast South MP, in a newspaper article.

The Prime Minister has asked officials to study the Smart Border 2.0 report – commissioned by a European parliamentary committee – as she scrambles for a solution to the border dilemma.

In December, she agreed to “full alignment” of regulations across the entire UK if necessary to avoid the return of border posts and checks, which could become a magnet for terrorists.

But she has been accused of reneging on that agreement, rejecting the EU’s proposal of a “common regulatory area” across Ireland if other solutions to avoid a hard border fail.

Instead, the Government has vowed to leave the EU customs union, putting its faith in technology to avoid checks – while failing to rule out the return of cameras at the crossing.

The Smart Border 2.0 study does propose a solution based on technology, but The Independent can report it acknowledges the plan would still require:

“Both physical and digital infrastructure” – with vehicles “to be monitored using Automatic Number Plate Recognition (ANPR) at unmanned border crossings”. It states: “CCTV will also be required at border crossings”

A Trusted Traveller Programme – under which people would “pre-register for fast-track movement across the border”, possibly using “biometric passports or enhanced drivers’ licenses using radio frequency identification”

“Free movement lanes” at the busiest crossings to “allow differentiation between those entitled or not to move under the CTA [Common Travel Area]. Non-qualifying individuals who did not cross at these specific border crossings would then be considered to have entered the state irregularly”

Agreement between the EU and the UK on the “transfer of personal data”, to allow each side to carry out inspections for the other. The EU has said this will require binding oversight by the European Court of Justice – which Ms May has ruled out

“The proposal does not remove the need for a border with checks; rather, it is designed to make such a border as frictionless and open as possible,” states the report, carried out for the European Parliament’s policy department for citizens’ rights and constitutional affairs.

A spokesperson for the Irish government’s Department of Foreign Affairs and Trade pointed to the phase one Brexit deal agreed by Ms May last December.

“The UK gave a guarantee that a hard border, including any physical infrastructure and associated checks and controls will be avoided. This report proposes the opposite.”

The biggest issues facing UK on leaving EU Show all 8 1 /8 The biggest issues facing UK on leaving EU The biggest issues facing UK on leaving EU Post-Brexit immigration workers sorting radishes on a production line at a farm in Norfolk. One possible post-Brexit immigration scheme could struggle to channel workers towards less attractive roles - while another may heighten the risk of labour exploitation, a new report warns. PA The biggest issues facing UK on leaving EU Customs union A key point in the negotiations remains Britain's access to, or withdrawal from, the EU customs union. Since the referendum there has been hot debate over the meaning of Brexit: would it entail a full withdrawal from the existing agreement, known as hard Brexit, or the soft version in which we would remain part of a common customs area for most goods, as Turkey does? No 10 has so far insisted that “Brexit means Brexit” and that Britain will be leaving the customs union, but may be inclined to change its position once the potential risks to the UK’s economic outlook become clearer. Alamy The biggest issues facing UK on leaving EU Northern Ireland-Irish border Though progress was made last year, there has still been no solid agreement on whether there should be a hard border between Northern Ireland and the Republic of Ireland. To ensure borderless travel on the island, the countries must be in regulatory alignment and therefore adhere to the same rules as the customs union. In December, the Conservative Party’s coalition partners, the DUP, refused a draft agreement that would place the UK/EU border in the Irish Sea due to its potential to undermine the union. May has promised that would not be the case and has suggested that a “specific solution” would need to be found. Getty The biggest issues facing UK on leaving EU Transition period Despite protests from a small number of Conservative MPs, the Government and the EU are largely in agreement that a transitional period is needed after Brexit. The talks, however, have reached an impasse. Though May has agreed that the UK will continue to contribute to the EU budget until 2021, the PM wants to be able to select which laws made during this time the UK will have to adhere to. Chief negotiator Michel Barnier has said the UK must adopt all of the laws passed during the transition, without any input from British ministers or MEPs. EPA The biggest issues facing UK on leaving EU Rights of EU citizens living the UK The Prime Minister has promised EU citizens already living in the UK the right to live and work here after Brexit, but the rights of those who arrive after Brexit day remains unclear. May insists that those who arrive during the transition period should not be allowed to stay, whereas the EU believe the cut-off point should be later. Getty The biggest issues facing UK on leaving EU Future trade agreement (with the EU) Despite this being a key issue in negotiations, the Government has yet to lay out exactly what it wants from a trade deal with the EU. Infighting within the Cabinet has prevented a solid position from being reached, with some MPs content that "no deal is better than a bad deal" while others rally behind single market access. The EU has already confirmed that access to the single market would be impossible without the UK remaining in the customs union. Getty The biggest issues facing UK on leaving EU Future trade agreements (internationally) The Government has already begun trying to woo foreign leaders into prospective trade agreements, with various high profile state visits to China, India and Canada for May, and the now infamous invitation to US President Donald Trump to visit London. However the UK cannot make trade agreements with another country while it is still a member of the EU, and the potential loss of trade with the world's major powers is a source of anxiety for the PM. The EU has said the UK cannot secure trade deals during the transition period. EPA The biggest issues facing UK on leaving EU Financial services Banks in the UK will be hit hard regardless of the Brexit outcome. The EU has refused to give British banks passporting rights to trade within the EU, dashing hopes of a special City deal. However according to new reports Germany has suggested allowing trade on the condition that the UK continues paying into the EU budget even after the transition period. Getty

And Mr Hain, a supporter of the pro-EU Open Britain group, added: “It is absolutely incredible that the Prime Minister has appeared to endorse this report and the proposals it contains.

“These ideas are more than just stupid, they are dangerous and, if we insisted on pre-registration for travellers, we would be risking immediate civil unrest.”

A government spokesman confirmed that Brexit officials were studying the Smart Border 2.0 report, after Ms May’s little-noticed comment in her Commons statement last Monday.

But he added: “This isn’t our report, it was produced by the EU. Our commitment remains that we want no hard border between Northern Ireland and the Republic of Ireland – and no physical infrastructure at the border.

“The Prime Minister has said that any number of times, and the position hasn’t changed.”

The criticism underlines how the future Irish border is among the most difficult issues in the Brexit negotiations, threatening to wreck the UK’s hopes for a deal.

In Dublin, on Friday, Donald Tusk, the president of the European Council, warned the EU will stall trade talks until Britain comes up with a workable solution.