President Donald Trump promised a lot would happen on “day one” during his election campaign – although he later clarified he meant on his first Monday in office, rather than today.

Apparently keen to get down to business, the billionaire tycoon went to the Oval Office immediately after yesterday’s swearing-in ceremony but before the inauguration ball.

The first order he signed related to Obamacare – which he has pledged to repeal.

The President signed an order to federal departments to “minimise the economic impact” of the Affordable Care Act, which grants health insurance to all Americans.

He then signed a stack of executive orders relating to his Cabinet appointments and other procedural matters.

One was a law to allow former Marine James Mattis to take the office of Defence Secretary, waiving the requirement that the appointee be a civilian for the past seven years.

In pictures: Protests, pomp and Donald Trump Show all 30 1 /30 In pictures: Protests, pomp and Donald Trump In pictures: Protests, pomp and Donald Trump President-elect Donald Trump acknowledges guests as he arrives on the platform at the US Capitol in Washington DC Getty Images In pictures: Protests, pomp and Donald Trump Donald Trump is sworn in as the 45th president of the United States by Chief Justice John Roberts as Melania Trump looks on during the 58th Presidential Inauguration at the U.S. Capitol in Washington AP In pictures: Protests, pomp and Donald Trump President Donald Trump shakes hands with Justice John Roberts after taking the oath at inauguration ceremonies swearing in Trump as the 45th president of the United States Reuters In pictures: Protests, pomp and Donald Trump President Donald Trump raises his fists after his inauguration on the West Front of the U.S. Capitol Getty In pictures: Protests, pomp and Donald Trump U.S. President-elect Donald Trump greets outgoing President Barack Obama before Trump is inaugurated during ceremonies on the Capitol in Washington Reuters In pictures: Protests, pomp and Donald Trump resident-elect Donald Trump arrives on the platform of the US Capitol in Washington DC Getty Images In pictures: Protests, pomp and Donald Trump Attendees partake in the inauguration ceremonies to swear in Donald Trump as the 45th president of the United States at the U.S. Capitol in Washington DC Reuters In pictures: Protests, pomp and Donald Trump US President Donald Trump delivers his inaugural address during ceremonies at the US Capitol in Washington DC Getty In pictures: Protests, pomp and Donald Trump U.S. President Donald Trump waves with wife Melania during the Inaugural Parade in Washington DC Reuters In pictures: Protests, pomp and Donald Trump Protesters registered their rage against the new president Friday in a chaotic confrontation with police who used pepper spray and stun grenades in a melee just blocks from Donald Trump's inaugural parade route. Scores were arrested for trashing property and attacking officers AP In pictures: Protests, pomp and Donald Trump Demonstrators protest against US President Donald Trump in Washington DC Getty Images In pictures: Protests, pomp and Donald Trump A woman holds a sign before the start of the Presidential Inauguration of Donald Trump at Freedom Plaza in Washington DC Getty Images In pictures: Protests, pomp and Donald Trump Anti-Trump protesters prepare banners for a protest against the inauguration of US President-elect Donald Trump, in Berlin REUTERS In pictures: Protests, pomp and Donald Trump Demonstrators shout slogans against US President-elect Donald Trump in Washington DC Getty Images In pictures: Protests, pomp and Donald Trump Demonstrators march, block foot traffic and clash with U.S. Capitol Police at the entry checkpoints for the Inauguration of Donald Trump Alamy Live News In pictures: Protests, pomp and Donald Trump Demonstrators display a banner as people arrive for US President-elect Donald Trump's inauguration in Washington DC Getty Images In pictures: Protests, pomp and Donald Trump A man displays a placard as people lineup to get into the National Mall for the inauguration of US President-elect Donald Trump in Washington DC Getty Images In pictures: Protests, pomp and Donald Trump Protesters demonstrating against U.S. President Donald Trump raise their hands as they are surrounded by police on the sidelines of the inauguration in Washington DC Reuters In pictures: Protests, pomp and Donald Trump A demonstrator wearing a mask depicting Donald Trump protests outside the US Embassy in London Getty Images In pictures: Protests, pomp and Donald Trump Demonstrators hold placards as they protest outside the US Embassy in London Getty Images In pictures: Protests, pomp and Donald Trump Former US President George W. Bush and First Lady Laura Bush arrive for the Presidential Inauguration at the US Capitol Rex In pictures: Protests, pomp and Donald Trump Michelle Obama and Dr. Jill Biden share an umbrella as President Donald Trump delivers his inaugural address at the inauguration in Washington DC Rex In pictures: Protests, pomp and Donald Trump Former Democratic presidential nominee Hillary Clinton and former President Bill Clinton arrive on the West Front of the U.S. Capitol in Washington Reuters In pictures: Protests, pomp and Donald Trump U.S. Vice President Mike Pence takes the oath of office on the West Front of the U.S. Capitol in Washington, DC Getty Images In pictures: Protests, pomp and Donald Trump Advisors to President-elect Donald Trump, Kellyanne Conway and Steve Bannon depart from services at St. John's Church during the Presidential Inauguration in Washington Reuters In pictures: Protests, pomp and Donald Trump Protesters demonstrating against U.S. President Donald Trump take cover as they are hit by pepper spray by police on the sidelines of the inauguration in Washington DC Reuters In pictures: Protests, pomp and Donald Trump An activist demonstrating against U.S. President Donald Trump is helped after being hit by pepper spray on the sidelines of the inauguration in Washington DC Reuters In pictures: Protests, pomp and Donald Trump A police officer tries to tackle a protester demonstrating against U.S. President Donald Trump Reuters/Adrees Latif In pictures: Protests, pomp and Donald Trump Police arrest and detain a protester in the street in Washington DC Rex In pictures: Protests, pomp and Donald Trump A police officer falls to the ground as another shoots pepper spray at protesters demonstrating against U.S. President Donald Trump on the sidelines of the inauguration in Washington DC Reuters

President Trump made further nominations for his Cabinet, including Scott Pruitt for head of the Environmental Protection Agency and John Kelly for the Department of Homeland Security.

Mr Trump also signed a proclamation creating a National Day of Patriotism, although it has not been announced on what day this will fall.

The new President returned a bust of Winston Churchill to the Oval Office apparently to acknowledge the famous “special relationship” between the UK and the US.

The bust of the wartime leader could be seen as the new President signed his first orders having reportedly been kept at The British Embassy during the Obama years, when it was replaced by one of civil rights leader Martin Luther King.

Shortly after President Trump was sworn in as the 45th President of the United States, all foreign ambassadors were fired and with no concrete replacement ambassadors lined up.

While he was President-elect, Mr Trump insisted that every ambassador appointed by former President Barack Obama would have to leave their office by midday on 20 January with no grace period.

It is common policy that political appointed ambassadors resign at the beginning of a new administration – but unusual to have no replacements confirmed at this stage.

Thousands attend Women's March on London protest against Trump

The official White House website has been given a make-over and President Trump’s agenda has replaced that of Barack Obama.

The new administration lists just six issues on the website - energy, foreign policy, jobs and growth, military, law enforcement and trade deals.

Critics have pointed to the fact there is no longer any mention of civil rights, LGBT rights, healthcare or climate change.

The previous references to climate change have been replaced by a new energy plan that makes no mention of global warming and commits only to helping Americans reduce the cost of their energy.

As well as moving into the White House with the new first family, President Trump took ownership of the official @POTUS (President of the United States) Twitter handle from Barack Obama.

Yesterday, tweets began appearing on the official @POTUS account, although these will be monitored by official advisers.

But this morning, the prolific tweeter sent his customary early morning tweet to his 21.1 million followers from his personal Twitter account, @realDonaldTrump, indicating that he will use both accounts simultaneously.

“A fantastic day and evening in Washing ton DC. Thanks to @FoxNews and so many other news outlets for the GREAT reviews of the speech!” he said on Twitter.

But the US Interior Department has reportedly been ordered to cease use of its official Twitter accounts after the National Park Service shared two tweets implicitly critical of President Trump during his inauguration.