The UK is this morning grieving the death of Queen Elizabeth II, the country’s longest-serving monarch.

Following the announcement of her passing by Buckingham Palace, several notable moments have already taken place, including her son becoming King Charles III, a speech by Prime Minister Liz Truss and tributes from leaders across the globe.

Worldwide tributes pour in for ‘remarkable’ Queen – latest updates

A state of mourning has officially begun across the country, which is set to remain until the Queen’s funeral is held.

What will be taking place on Friday to mark Her Majesty’s death?

The King and his Queen Consort Camilla will return to London from Balmoral, with the monarch due to hold his first audience with Prime Minister Liz Truss.

The House of Commons’ sitting will not start at 9.30am as planned, with both Houses of Parliament due to gather at noon instead.

MPs and peers will be invited to pay tribute to the Queen in the session, led by Ms Truss, which is set to last until 10pm.

The government is not expected to announce any other business, unless anything urgent occurs, to allow focus to fall entirely on the Queen during the 10-hour sitting.

Read more: From the new King to national mourning – this is what happens now

Ms Truss and senior ministers will also attend a public service of remembrance at St Paul’s Cathedral in central London during the day.

The government is then due to confirm the length of national mourning, which is likely to be around 12 days, from now up to the day after the Queen’s funeral.

It will also announce that the funeral day will be a public holiday in the form of a Day of National Mourning.

Throughout the course of Friday, King Charles is likely to meet the Earl Marshal – the Duke of Norfolk – who is in charge of the Queen’s funeral, to approve the carefully choreographed schedule for the coming days.

He will decide on the length of court or royal mourning for members of the Royal Family and royal households, which is expected to last a month.

In the evening, His Majesty is expected to address the nation in a televised speech, where he will pay tribute to his mother and pledge to serve as head of state.

In central London, 96 rounds of gun salutes – one for every year of the Queen’s life – will be fired in tribute to the late monarch.

Churches have also been urged to toll their bells, with the Church of England sending out guidance to parishes, chapels and cathedrals across the country encouraging them to open for prayer or special services.

The Central Council of Church Bell Ringers has recommended tolling muffled bells for one hour from noon.

Bells will ring out at Westminster Abbey, St Paul’s Cathedral and Windsor Castle.

What will happen on Saturday?

Unusually, the House of Commons will hold a sitting on Saturday to allow senior MPs to take the oath of allegiance to King Charles III.

This will begin at 2pm and will be followed by tributes, which will continue until 10pm.

The session will end with a “formal humble address” to the King at the end, “expressing the deep sympathy of the House” on the Queen’s death, the House of Commons’ said in a statement.

All MPs will have the option to take the oath to the King when the House returns, but are not obliged to.

Commons Speaker Sir Lindsay Hoyle will determine the timetable for the following days, but it is expected to be significantly reduced until after the state funeral as Parliament adjourns.

This means new laws cannot be passed until Parliament returns, though it could be recalled for the most pressing matters.

Also on Saturday morning, an Accession Council will meet at St James’s Palace in London to formally proclaim Charles as the new sovereign.

The first public proclamation of the new sovereign will then be read in the open air from the Friary Court balcony at St James’s Palace by the Garter King of Arms.

Union flags go back up to full-mast at 1pm and remain there for 24 hours to coincide with the proclamations before returning to half-mast.