A ring of steel was placed around Stormont last night as security was heightened in preparation for the visit of US President George Bush.
Mr Bush, flying in from London on the presidential Airforce One airplane, is due to arrive in Belfast later today, accompanied by his wife Laura for the final stop on his European farewell tour before leaving office in January.
The president, who met Gordon Brown in the UK capital yesterday for talks on Iraq and other issues, is expected to be greeted at Belfast International Airport by the Prime Minister, who, along with his wife Sarah, will travel to Aldergrove by government jet.
Under tight security, Mr Bush will then begin the execution of a whistle-stop agenda, said to include a visit to Stormont Castle and a local primary school.
First up, Mr Bush and Mr Brown are due to meet new First Minister Peter Robinson and Deputy First Minister Martin McGuinness at Stormont Castle, where their offices are based.
Dr Ian Paisley — who has enjoyed a good relationship with the US leader since his visit to the States last year — will also be present to shake Bush's hand for the last time before he leaves office.
Bush is thought to want to put his seal of approval on devolution, having been invited to do so by the then DUP First Minister and Martin McGuinness, when they visited him at the White House last December.
Reports suggest that George Bush was rather taken with the two leaders and, instead of their allotted 15 minutes, spent more than a hour speaking to them about how he could help the new administration.
Meanwhile, the First Lady and Sarah Brown are understood to have a separate programme to follow, details of which cannot be revealed for security reasons.
After the Stormont audience, the US leader is scheduled to visit a local primary school, where he will be joined once again by the First Lady. The couple are expected to meet pupils and staff, where cross-community schooling is likely to one of the main topics of discussion.
The school's identity is being kept secret but heightened security around a primary in south-east Belfast prompted speculation in the local community.
Mr and Mrs Brown are understood to have made alternative arrangements while the president and his wife will be fulfilling the school engagement.
Motorists are being warned to expect widespread traffic disruption today and a helicopter exclusion zone will be in place in the skies above Belfast.
Bush's Belfast visit is nevertheless set to be marked by protests from anti-war campaigners unhappy at the reception for the architect of the wars in Iraq and Afghanistan.
Ahead of his visit yesterday, Amnesty International staged a demonstration to voice concerns about prisoner treatment and the detention of terror suspects.
And today, two further protests are expected at City Hall at 12.30pm and at Stormont at 2.30pm, organised by the Bush Not Welcome Group and Belfast Anti-War movement.
Amid tight security controls, the Stormont estate is to be closed off for nearly 48 hours, and there will be flight exclusion orders over the city.
The government said the estate, including the Mo Mowlam Children's Park, which was closed to the public at the weekend, will remain shut today.
Assembly and essential staff will be able to get into the Assembly building today, but there will be no Assembly session and no Stormont committees, and those politicians who do make it in will have to stay in the building for the duration of the President's visit.
Previously, Mr Bush came to Northern Ireland in 2003 for a summit at Hillsborough with Tony Blair.
In total, the president, who has also visited Slovenia, Germany, Italy, the Vatican City and Paris, will only spend 24 hours in the UK before departure.
After a hectic programme in the province, Airforce One has been primed to whisk the most powerful man in the world and his wife out of Northern Ireland at around tea-time today.