George Hamilton told MPs there was no coordinator who was “actually taking responsibility” for the project – as he warned of the risk from organised crime and dissident terrorists.
The chief constable revealed he had yet to submit a business case for how to bolster border policing because he was “trying to find a mechanism and an audience” for doing so.
“We feel like we are in the dark around all of this – we don’t have that go-to coordinator to assist with us, to tell us what the requirement is,” Mr Hamilton said.
The evidence was described as “very troubling” by Sylvia Hermon, an independent Northern Ireland MP – while the DUP’s Ian Paisley Jnr said it “sounds like a shambles”.
Mr Hamilton also revealed he had yet to have a meeting with Theresa May about the Brexit threat to the border – and that he had not met her at all since last October.
“There are so many issues to be dealt with, in such a period of time, that things are not getting the attention they require,” he told the Commons Northern Ireland committee.
And he added: “The clock is ticking – time is running out.”
The prime minister’s lack of attention to the crucial issue was attacked by Lady Hermon, who described it as “extraordinary”.
“She was the home secretary for six years. She is well aware – above many in the cabinet – of the delicacy and the difficulties that the PSNI [Police Service of Northern Ireland] is going to face, whether it’s a soft or a hard Brexit.”
Confirming the renewed terrorist threat from a harder border, Mr Hamilton said: “The New IRA themselves have come out saying that – they have talked about Brexit being an opportunity for them. That would be our assessment.”
The EU had demanded progress on the Irish border controversy by this week’s leaders’ summit – but none is now expected to be made before the autumn.
The issue is caught up in cabinet disagreements over future customs arrangements, which the prime minister hopes to settle at a Chequers “away day” on 6 July.
She has promised “no physical infrastructure”, but anti-EU Tories have demanded the UK plough ahead with pulling out of the EU single market and customs union – leaving the question of future border checks to Dublin to decide.
Meanwhile, the EU has rejected the UK’s plans for untested smart technology to solve the border impasse – warning it would fail to deliver the promised open border.
Preparations have also likely to have been hit by the absence of devolved government in Belfast, which collapsed 17 months ago.
Mr Hamilton also raised his fears about the UK’s likely ejection from the European arrest warrant, because of Ms May’s “red line” of ending jurisdiction by the European Court of Justice.
He said there were “countless examples of rapists and foreign criminals that have been brought from EU countries”.
“It is a key issue for policing, for law enforcement,” he told the inquiry, adding: “It’s a very real issue for us.”
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