The incoming Irish prime minister has admitted mistakes were made on both sides during negotiations for a post-Brexit deal between the UK and the EU, but has promised to be "flexible and reasonable" when talks of amending the Northern Ireland protocol resume in 2023.

Leo Varadkar, who was Taoiseach during the negotiation period and began his second term in office in December, told reporters in Dublin that he plans to head to Northern Ireland early in the year to work out a solution on contentious issues such as customs checks on goods traveling between Northern Ireland and the rest of the UK.

He also acknowledged that the original protocol may have been too restrictive, saying: "One thing I have said in the past is that, when we designed the protocol, when it was originally negotiated, perhaps it was a little bit too strict."

This may give a boost to politicians seeking to ease rules on the movement of goods between Great Britain and Northern Ireland, which remains part of the EU single market, in order to ensure an open border between the north and the Republic.

The Protocol has never been fully implemented after the UK abandoned checks on certain goods, such as fresh food, at Northern Irish ports. Mr Varadkar conceded that this lack of enforcement has not had the negative impact the EU feared.

He said: "We've seen that the protocol has worked without it being fully enforced. And that's why I think there is room for flexibility and room for changes, and we're open to that."

Mr Varadkar added that this view is shared by European Commission president Ursula von der Leyen and vice-president Maroš Šefčovič, who has responsibility for overseeing the UK Trade and Cooperation Agreement.

There are hopes that progress on the Protocol can be made before 19th January, which is the deadline set by the UK to call fresh elections for Northern Ireland's devolved government.