David Davis said the Tories were singing from the same hymn sheet on the terms of a Brexit transition. Picture by PA Wire

Taoiseach Leo Varadkar Taoiseach has said that it is up to Britain to "square the circle" of avoiding a hard border.

The Fine Gael leader told CNN that a hard border could be avoided either through a new EU-UK partnership or by a "unique solution" for Northern Ireland.

Asked how the apparent contradiction between avoiding a border and the demands by the pro-Brexit camp that the UK stay outside the single market, the taoiseach said: "I would humbly suggest that it is for the people who are leaving to square that circle, and not others."

He added: "One way that it could be done, for example, is through a new EU-UK agreement, a new partnership that in many ways may not be the single market but could be very similar to it."

Earlier in the week, Mr Varadkar alluded to a "Norway-plus" model for any deal.

He said said that while the final deal may not see the UK remain in the Customs Union, the arrangements "may be very similar to it, to replicate what's there already, in terms of regulatory alignment".

The taoiseach rejected the suggestion that December's agreement on avoiding a hard border was a fudge.

"It is my job and the job of others to make sure that doesn't happen," he said.

"It can be done in two ways – a new relationship between the EU and the UK that replicates the single market and the customs union, or it needs to be a unique solution for Northern Ireland."

When it was suggested that such a scenario would "not play well" with the DUP, the Taoiseach replied: "It might play well with the majority of people in Northern Ireland who perhaps would see the advantages of having it both ways.

"If there's any part of the United Kingdom which actually can have flexibility and can have the benefits, it is Northern Ireland."

Meanwhile, David Davis has said there is "no difference" between him, the chancellor and prime minister following a Tory row over the terms of a Brexit transition.

The Brexit secretary said all three wanted the UK's exit from the EU in March 2019 to "serve the British economy... and the British people".

There was a "diversity of views" in all parties and EU member states, he said.

Backbench Tories had criticised Philip Hammond for saying that changes to UK-EU relations could be "very modest".

No 10 distanced itself from the chancellor's remarks and one Tory MP said he should "stick to the script" the PM had laid out.

Following a speech outlining some of his ambitions for an "implementation period" immediately after the UK leaves the EU in March 2019, Mr Davis was asked about the row.

He said the chancellor had "made clear" the UK would be outside the EU customs union and single market but initially there would be "very little initial difference between the standards and regulations that would apply" in the UK and in the EU - allowing little disruption to access to markets.