Queen Elizabeth II has summoned her grandson Prince Harry for face-to-face talks on Monday to discuss future roles for him and his wife Meghan Markle following the couple’s bombshell announcement that they want to step back from Britain’s royal duties.

Prince Harry, the Duke of Sussex, his brother William, the Duke of Cambridge, and their father Charles, the Prince of Wales, have all been invited to the meeting at the Queen’s Sandringham estate in Norfolk, while Meghan is expected join the discussion over the phone from Canada where she is with the couple’s eight-month-old son Archie.

Monday’s meeting will be the first time the 93-year-old monarch has come face-to-face with Harry since the Sussex crisis exploded. It will determine the couple’s future roles and decide if they will retain their royal titles as the Duke and Duchess of Sussex.

The couple made their bombshell announcement on Wednesday that they intend to “step back” from being frontline royals, split their time between the UK and North America, and work towards becoming “financially independent”.

According to royal insiders, the so-called Sandringham Summit, is expected to thrash out some of the key details but a complete resolution to the couple’s expressed wish to split their time between the UK and North America and become financially independent is unlikely to be achieved at the end of Monday’s meeting.

There are likely to be tax implications as a result of such unprecedented changes to their residential and financial status as royals.

A concrete plan is expected to be broadly agreed and publicly announced some time in the coming week, with details left to be fleshed out over time.

Some of the issues to be discussed at the crisis talks would include how much “official” royal work Harry, 35, and Meghan, 38, will do in the UK and overseas on behalf of the royal family and the government.

It will also discuss Harry and Meghan’s His and Her Royal Highness titles, and how they will be styled; how much money they might receive from the Queen and Prince Charles once their Sovereign Grant public funding is cut; and what commercial deals the couple might be allowed to strike.

The crunch meeting presided over by the 93-year-old monarch, being dubbed a family showdown, will present Harry with a range of draft written proposals – compiled by a team of aides and private secretaries.

It is hoped that when a deal is finally agreed for the way in which the Sussexes will spend their future lives, it will form a blueprint for future royal generations, including Princess Charlotte and Prince Louis – the children of William and Kate who are not in the direct line of succession for the British crown.

Meanwhile, William has spoken of his “sadness” at the broken bond with his younger brother.