Under the new backstop proposals, if no agreement on customs has been implemented by the end of 2020, a temporary arrangement would ensure that no "tariffs, quotas, rules of origin (or) customs processes" applied to UK-EU trade.
"Details of whether or not the country will have a transition/implementation period are still unclear and there is still no decision on what customs arrangements we will have from March 2019 onwards". But he had some objections: he said it can't be time-limited, shooting down one of the conditions that's key for Brexit supporters in May's Cabinet.
She said the Government was "committed to making sure that the future arrangements are in place by the end of December 2021 at the very latest" and to ensuring the United Kingdom leaves the customs union.
"Is it a workable solution to avoid a hard border?" Does it respect the integrity of the single market/customs union?
DUP deputy leader Nigel Dodds said: "The backstop in the technical report issued applies to the entire United Kingdom".
Mr Thompson said HMRC had chosen to assess the potential impact by looking at the how many customs declarations there will be and the cost of that rather than as a percentage of the value of trade.
However, the European Parliament's chief negotiator, Guy Verhofstadt, warned against trying to impose a time limit, saying: "A backstop that is temporary is not a backstop".
The prime minister and the opposition Labour Party have repeatedly ruled out the possibility of a second referendum, saying Britain will leave the European Union in March next year. While both sides say they want to keep the border between Northern Ireland and the Republic of Ireland open, the proposals each side has come up with to achieve that are unacceptable to the other side.
"After weeks of the government negotiating with itself, the fudged document they have produced doesn't engage with any of the key Brexit dilemmas", said opposition Labour MP Chris Leslie.
The prime minister also held separate face-to-face discussions in her parliamentary office with the two other leading Brexiteers, foreign secretary Boris Johnson and global trade secretary Liam Fox.
On Wednesday reporters asked Davis if he would quit if the backstop did not have his explicit approval, replying: "That's a question I think for the prime minister, to be honest".