A senior EU source said the United Kingdom prime minister would need determine whether she could sell an open-ended customs union to her party, but the calculation in Brussels was that it would be acceptable to the House of Commons as a whole. The EU has to date rejected a temporary customs union.
The report claims an "all-UK customs deal" will be written into the legally binding withdrawal agreement, which would do away with the need for the controversial "backstop" arrangement agreed by the United Kingdom last December, which would see Northern Ireland remain in full alignment with the EU's single market and customs union rules in the event of a no-deal Brexit.
The backstop is a key aspect of the Brexit Withdrawal Agreement which the European Union and United Kingdom signed up to in December.
A Downing Street spokesman said May and Varadkar agreed "the intention was that the backstop should only be a temporary arrangement".
"Obviously still having this issue in relation to the insurance arrangements for Northern Ireland and Ireland, and that very much remains our focus and attention in getting that deal".
Mr Raab's proposal was put to the Irish deputy prime minister Simon Coveney in a private meeting in London last Tuesday, but three days later was apparently contradicted by David Lidington, the UK's de facto deputy prime minister, on a visit to Dublin.
Irish premier Leo Varadkar has told Theresa May that he will not accept a Brexit deal which gives the United Kingdom the unilateral power to halt "backstop" arrangements for the border with Northern Ireland.
It has so far suggested a backstop that would see the United Kingdom as a whole remaining aligned with the EU customs union, possibly for a limited time.
"We are making good progress on the future relationship, and 95% of the Withdrawal Agreement has been settled".
Former Goldman Sachs bankers and Jho Low charged in Malaysian financial scandal
A lawyer for Leissner was unavailable for comment when NPR phoned. It was not immediately clear who is representing Ng. He has called the Malaysian charges political.
"I said so back then and I'm still concerned now".
Following a phone conversation with Mrs May on Monday morning, the Taoiseach said both leaders emphasised their commitment to avoiding a hard border in Ireland and the need for a legally operable backstop.
Mr Brokenshire, appearing on television, was asked if a deal was close, replying: "Well, we want to get that deal, we're obviously working hard to see that that happens".
"In March the United Kingdom agreed this backstop will apply "unless and until" a close future relationship eliminates any need for border infrastructure or related checks and controls".
Under the banner headline "Revealed: Theresa May's secret Brexit deal", The Sunday Times said the European Union accepts that regulatory checks on goods can be carried out in factories and shops rather than at the border.
"While we too hope the Northern Ireland backstop will never be required to be used, it will be required to be written down in legal text".
"As soon as MPs understand what is really at stake, I have no doubt that they will throw this deal out".