UK Prime Minister Liz Truss and US President Joe Biden "agreed on the importance of protecting" peace in Northern Ireland, in a phone call this evening.

Ms Truss has spearheaded legislation in the British parliament that would unilaterally override parts of a UK-EU post-Brexit trade pact for Northern Ireland, which Brussels opposes and also threatens to strain relations with Washington.

"The Prime Minister looked forward to working closely with President Biden as leaders of free democracies to tackle shared challenges, particularly the extreme economic problems unleashed by [Vladimir] Putin's war," a Downing Street spokeswoman said.

It comes as Conservative MP Chris Heaton-Harris has been appointed Secretary of State for Northern Ireland.

Minister for Foreign Affairs Simon Coveney congratulated Mr Heaton-Harris, adding that the Northern Ireland Secretary's first job should be a functioning executive for Northern Ireland.

"I've known him since we were both members of the European Parliament & I look forward to working closely with him in the coming months," Mr Coveney wrote on social media.

DUP leader Jeffrey Donaldson requested an urgent meeting with Mr Heaton-Harris to "press home the priorities for Northern Ireland".

Throughout the evening, Ms Truss has been appointing a new cabinet - one where for the first time a white man will not hold one of the country's most important ministerial positions.

Earlier this evening, Ms Truss spoke with Ukrainian President Volodymyr Zelensky in her first call with a foreign leader.

She accepted an invitation to visit Ukraine and reiterated her support for the country which was invaded by Russia in February.

Britain has been a major backer of Ukraine, sending almost 7,000 anti-tank weapons, hundreds of missiles and armoured fighting vehicles. It is also training Ukrainian soldiers.

Liz Truss spoke with Ukrainian President Volodymyr Zelensky in her first call with a foreign leader

A statement said Ms Truss reiterate the UK's "steadfast support for Ukraine's freedom and democracy".

Earlier, in her first address as UK Prime Minister, Ms Truss vowed action to address a series of immediate challenges.

This morning, she flew to the British royal family's Scottish home to be asked by the UK's Queen Elizabeth to form a government. She replaces Boris Johnson who was forced out after three tumultuous years in power.

Liz Truss met Queen Elizabeth in Balmoral this afternoon
Liz Truss met Queen Elizabeth in Balmoral this afternoon

"We now face severe global headwinds caused by Russia's appalling war in Ukraine and the aftermath of Covid," the 47-year-old former foreign secretary said outside her Downing Street office.

"I am confident that together we can ride out the storm. We can rebuild our economy, and we can become the modern brilliant Britain that I know we can be."

Ms Truss said she had three priorities: growing the economy through tax cuts, dealing with rising energy costs from this week and ensuring people got the care they needed from the state-run National Health Service.

"As strong as the storm may be, I know the British people are stronger."

However, she inherits an economy in crisis, with inflation at double digits, the cost of energy soaring and the Bank of England warning of a lengthy recession by the end of this year. Already, workers across the economy have gone on strike.

Her plan to revive growth through tax cuts, while also potentially providing around £100 billion for energy, has rattled financial markets, prompting investors to dump the pound and government bonds in recent weeks.

Ms Truss has also promised to scrap plans to increase corporation tax on big firms, and to reverse an increase in a payroll tax on workers and employers, designed to raise additional funding for health and social care, with the extra spending coming from general taxation.

During her address, she also paid tribute to her predecessor Boris Johnson, who she said history will remember as a "hugely consequential prime minister".

Ms Truss did not mention the Northern Ireland Protocol during her address, which was delayed due to heavy rain.

She is now in the process of appointing her new cabinet, with Shailesh Vara no longer continuing as Northern Ireland Secretary.

The queen had earlier accepted the resignation of Mr Johnson at an audience in Balmoral.

Taoiseach Micheál Martin congratulated Ms Truss, indicating that they would be having a conversation in the coming days.

In a statement, he said: "A shared history and close ties of people, of economy, and of culture link our two countries. A strong partnership between our two governments is vital to underpin the Good Friday Agreement and support peace and prosperity on these islands."

Mr Martin said that he hopes "we can use the period ahead to prioritise EU-UK engagement, and to reach agreed outcomes on the issues around implementation of the Northern Ireland Protocol".

The lectern had been removed prior to Liz Truss's address due to heavy rain

Saying he is looking forward to "close cooperation" with the new British leader, Mr Martin added: "I am committed to a strong and deep relationship between our countries, and to working in an open and constructive way with Prime Minister Truss."

Speaking this afternoon in Shannonbridge, he said: "I think there are officials at work in terms of setting up an engagement and a conversation with the British Prime Minister."

Some positive news on energy for first day in No 10

New Prime Minister Liz Truss has started on her first day with some good news as Sterling received a boost on reports of an energy bill freeze.

The pound went up in value by 0.8% against the dollar to $1.16 after sliding to its lowest level for over two years the previous day.

A weakening pound had been one of the symptoms of Britain's vulnerable economy.

Sterling strengthened after reports by Bloomberg and the BBC that Ms Truss will announce a new plan to stop further hikes in gas and electricity bills.

The plan is that energy companies will get government guaranteed loans to cover any further increases in wholesale prices so they will not be passed onto consumers immediately.

The freeze would cost around £130 billion and last 18 months to cover both domestic and business consumers.

However, it will the consumers who eventually pay back the money through their bills over a period of up to 20 years.

It will be welcome news for struggling households who were facing a further 80% price hike this winter.

According to the financial media outlets, this Sterling boost may be temporary and doubts remain over the sustainability of Ms Truss' plan to pay for tax cuts by borrowing more money at a time of rising interest rates and double digit inflation.

However, the new British Prime Minister can now point to some positive news on her first day.

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Additional reporting PA