Boris Johnson is still insisting there will be a bridge between Northern Ireland and Britain - and that a border in the Irish Sea will be "over my dead body".
Visiting on Thursday for a series of engagements and meetings with political leaders, the Prime Minister reiterated his message that the bridge would help bring the UK closer together.
The plan, which has been ridiculed by many, is part of his "build, build, build" agenda.
The span from Portpatrick to Larne would be 28 miles long and cost in the region of £20bn to build.
Although Mr Johnson previously estimated the cost at around £15bn.
The Prime Minister was speaking on a visit to the Ambulance Service HQ in Belfast on Thursday afternoon.
Earlier he had announced plans to establish a centenary forum and a centenary historical advisory panel to help mark the anniversary of Northern Ireland's foundation.
Mr Johnson discussed the centenary events during meetings with First Minister Arlene Foster, Deputy First Minister Michelle O'Neill and Taoiseach Micheal Martin at Hillsborough Castle in Co Down.
When asked if the bridge would be a good way to mark the centenary next year, the Prime Minister said: "I don't think it's going to be built next year, but let me be absolutely clear that as Prime Minister of the UK, I look at lots of different ways in which UK transport connectivity could be improved.
"Those links haven't been as strong as they used to be and we should certainly look at that possibility and we're doing some work on it right now."
Mr Johnson confirmed that Network Rail chair Sir Peter Hendy is to examine "the whole issue of Union connectivity" and will be reporting back to the Government "in due course", after which a decision will be made on whether or not to proceed with the plan.
The Prime Minister also insisted that there would be "no border down the Irish Sea" following Brexit.
He reiterated his promise that businesses here will enjoy unfettered access to markets in England, Scotland and Wales.
Business leaders here have expressed concern that red tape on goods crossing from Britain could make some trade unviable.
Mr Johnson has also agreed to "intensify" partnership arrangements with the Republic, and said more work could be done on bilateral deals.
He insisted: "There will be no border down the Irish Sea - over my dead body.
"It is important to have the protocol because we need also to protect that freedom of movement for goods, for people, for services north-south as well."
The next round of Brexit talks will begin on August 18 between the Prime Minister's adviser David Frost and the European Union's Michel Barnier in Brussels.
Under the protocol, if no wider trade deal is secured with the EU, tariffs would have to be paid on goods travelling from Britain into the Republic and the rest of the EU via Northern Ireland.
Which goods are at risk of tarrifs is still to be decided in negotiations with Brussels.
The EU is keen to ensure Northern Ireland does not become a backdoor entry point to its single market.
The port of Larne is preparing to install a border control post, and the UK has announced extra funding for borders with the EU.
Taoiseach Mr Martin expressed confidence that a "landing zone" exists for the EU and UK to strike a trade deal before the end of the year and he hopes for a "productive outcome" when Brexit negotiations resume.
Mr Martin said both sides knew that they needed to avoid another economic shock following Covid-19.
"It seems to me that there is a landing zone if that will is there on both sides, and I think it is, on the European Union side and on the British side, to find that landing zone," he added.