The Democratic Unionist Party will demand more cash in “the coming weeks” to continue propping up the Conservatives in power, in an early warning to Boris Johnson.

Arlene Foster revealed she spoke with the incoming prime minister soon after his victory was declared – and that she immediately put him on notice.

But she added: “That agreement included a review between each parliamentary session.

“This will take place over the coming weeks and will explore the policy priorities of both parties for the next parliamentary session.”

The DUP is widely expected to demand an even higher price to renew the agreement, as well as action to thwart prosecutions of soldiers investigated for alleged wrongdoing during the Troubles.

Boris Johnson's famous relatives Show all 11 1 /11 Boris Johnson's famous relatives Boris Johnson's famous relatives 1. King George II of Great Britain and Ireland, Elector of Hanover (1683 to 1760) Boris Johnson is a Hanoverian, and, thus distantly related to the Queen, David Cameron (via William IV) and Danny Dyer (via Edward III), among others. Boris's paternal grandmother, Yvonne Eileen Williams, known in the family as "Granny Butter" and whose family name was de Pfeffel, was a descendant of Prince Paul Von Wurttemberg. The German prince was, in turn, a direct descendant of George II. Discovered by genealogists f other BBC’s Who Do You Think You Are, Johnson commented, in 2008: "I felt I was the product of newcomers to Britain so it is totally bizarre, surreal in fact, to be told that in fact my Great x 8 Granddad is George II. But don't neglect the point that he shares that distinction with 1,023 others – there must be several thousand other people out there in the same position.” National Portrait Gallery Boris Johnson's famous relatives 2. The “Mummy of Basel”, Anna Catharina Bischoff (1719 to 1787) Last year, scientists in the Swiss city of Basel solved a decades-old mystery over the identity of a mummified woman. DNA extracted from the mummy’s gig toe indicates that the female is a great-great-great-great-great-great-great grandmother of Boris Johnson. The body was uncovered in 1975 while renovations were being done on Basel's Barfüsser Church, and was buried at the altar, wearing fine clothes, indicating she was at least well-to-do if not nobility. High levels of mercury in her remains suggested she had been treated for syphilis (the metal also helped preserve her). National Gallery of Basel Boris Johnson's famous relatives 3. Ali Kemal (1867 to 1922) (Pictured with wife Winifred Brun) For a man who made so much capital in the 2016 referendum on the prospect of Turkey joining the EU and its 80 million citizens thus enjoying free movement to the UK, Boris Johnson sometimes makes a surprisingly big deal of his Turkish Muslim great-grandfather on his father’s side, who he claims was an asylum seeker. Ali Kemal, according to his famous descendant, came to Britain because it was “a beacon of generosity and openness”. I t might be overstating it, but he did live in exile in England for a time. Unknown Boris Johnson's famous relatives 4. George Williams (1821 to 1905) Sir George, as he became, is the great (x4) grandfather of Boris Johnson, and was one of the founders of the Young Men’s Christian Association or YMCA, in 1841. An evangelical apostle of “muscular Christianity”, George took it upon himself to organise some fellow drapers and establish a safe place for young men where they could be shielded from the debauchery and the temptations of the flesh and the grape. No sofas would suffer red wine stains in the hostel. Since then it has gone global, today assisting 58 million people across 119 countries, which is almost as many as Boris helps. A social visionary of his time, George was knighted for his works by Queen Victoria in 1894. National Portrait Gallery Boris Johnson's famous relatives 6. King Friedrich of Wurttemberg (1754 to 1816) Though stocky of build, and handy in a game of rugger, Boris Johnson is not especially heavy or tall. This ancestor was. King Friedrich stood 6 foot 11 inches, and weighed 31 stone (2.12 metres/200 kilograms). Napoleon remarked that God had created the Prince to demonstrate the utmost extent to which the human skin could be stretched without bursting. There are rumours that he was bisexual and enjoyed the close companionship of young noblemen. This added to the strains on his marriage to Augusta, who was the granddaughter of King George II. One of their four children, Prince Paul is the link to the Johnsons, via an illegitimate daughter he fathered in Paris with an actor named Friederike Margrethe Porth. Ludwigsburg Castle Archive Boris Johnson's famous relatives 7. Professor Elias Lowe (1879 to 1969) Elias is Boris Johnson’s mother Charlotte’s great grandfather. The distinguished Princeton scholar and student of ancient scriptures (palaeographer) , Elias arrived in the United States as a refugee from Lithuania in 1891, and was affine of Albert Einstein. Jewish, Lowe came for a line of revered rabbis. Although he cannot be counted Hallachially Jewish, the Jewish Chronicle makes him 5 per cent Jewish on their reckoning. Rutgers School of Arts and Sciences Boris Johnson's famous relatives 8. Helen Lowe-Porter (1876 to 1963) Helen Tracey Lowe-Porter. is Boris Johnson's mother Charlotte’s great grandmother. An American, she married the Lithuanian-born academic Elisa Lowe, and is said to have been probably the most prominent literary translator in the English-speaking world working from German to English in the twentieth century. However, not necessarily the best and in such circles her reputation is contested. In any event, she retained for 50 years the exclusive rights to translate the works of her friend Thomas Mann. Her and Elias’ daughter Beatrice is Charlotte Johnson (nee Fawcett’s) mother. Lowe-Porter family Boris Johnson's famous relatives 9. Sir Henry Fawcett MP (1833 to 1884) Before Boris and Jo Johnson became MPs and minsters, there was Sir Henry Fawcett – Britain’s first blind MP. He was the husband of the famous suffragette Millicent Garrett Fawcett, and thus an ancestor of Boris on his mother’s side - though the family tree isn’t clear on how close they are related. Glasgow University Boris Johnson's famous relatives 10. Prince Paul of Wurttemberg (1785 to 1852) Odd looking, an amusing womaniser (remind you of anyone?), this minor German aristocrat was the progenitor of the Johnson’s posh pedigree, such as it is. His affair with an actress is Paris, Fredericke Porth, gave rise to a daughter (out of wedlock as they used to say) provided the link back to the royal families of Wurttemberg and Hanover, and thus of Great Britain. By the same token it means that Stanley, Boris, Rachel, Leo and Jo, and the rest of them along that branch of the tree, are also distantly related to most of the royal families of Europe including the Russian Romanovs – Johnson stands connected, albeit tenuously, to the Belgian, Danish, Dutch, Luxembourg, Norwegian and Swedish families, plus the German Kaiser. Paul had five declared children, and two illegitimate ones, at least that are known about. National Archive Holland Boris Johnson's famous relatives 11. Fredericke Porth (1777 to 1860) When, on the BBC show Who Do You Think You Are? Boris Johnson discovered the identity of his 4x Great Grandmother, Fredericke, he was just a touch chauvinist: “An actress, could be a euphemism we may be about to turn up a prostitute here. Not that I mind. I want you to know they can get up to anything, my ancestors, they have carte blanche to commit whatever acts of fornication they want as far as I am concerned, but I want to know”. It seems Fredericke Margarethe was indeed an actress for most of her life, and was widowed by the time her illegitimate daughter, the product of her affair with Prince Paul of Wurttemberg was born, in 1805. Born Porth, Fredericke was married to a man named Vohs until 1804, and, in 1818, remarried to a man named Werdy. She was described as a “Royal Saxon Court-Actress”. Alamy Stock Photo Boris Johnson's famous relatives 12. Millicent Garrett Fawcett (1847 to 1929) Disappointingly, the ancestor who is sometimes mentioned as a stands as a standing genealogical reproach to Boris Johnson may not be a related at all. As a pioneering feminist and suffragette, she’d surely disapprove of Boris’ attitudes towards womankind. As President of the National Union of Women’s Suffrage Societies (NUWSS), the largest component of the suffragette movement, she did as much as anyone to get women into the political life of the nation, and the Fawcett Society, still fighting for equal human rights, is named in her honour. Millicent lived just long enough to see the vote being granted on an equal basis to all women, and said this when it was finally enacted in 1928: “It is almost exactly 61 years ago since I heard John Stuart Mill introduce his suffrage amendment to the Reform Bill on May 20th, 1867. So I have had extraordinary good luck in having seen the struggle from the beginning.” Bain News Service/Elliott & Fry

Mr Johnson will need the support of the DUP even more than his predecessor did, as even the flimsy working majority she negotiated with the Northern Ireland party crumbles.

He will inherit a majority of just two – including the 10 DUP MPs – which will fall to only one if, as expected, the Liberal Democrats win the Brecon and Radnorshire by-election next week.

Some of his aides are already wargaming a snap autumn general election, as the likely only way to meet his pledge to leave the EU on Halloween, “deal or no deal”.

In a statement, Ms Foster said: “I have spoken with Boris Johnson and congratulated him on becoming leader of the Conservative Party.”

And she added: “I also look forward to welcoming Mr Johnson back to Northern Ireland shortly after he becomes prime minister.”

Mr Johnson is widely expected to carry out a whistlestop tour of Edinburgh, Cardiff and Belfast in the coming days, to emphasise his commitment to preserving the United Kingdom – which could be threatened by Brexit.

The DUP refused to back the Brexit withdrawal deal because it feared the threat to the union from the Irish backstop, so will expect the new prime minister to stick to his vow that it must be “junked”.

Mr Johnson has already been keen to stay close to the party, speaking at its conference last year and securing a Stormont photo with Ms Foster a few weeks ago.

Significantly, he has vowed to end prosecutions of veterans who served in Northern Ireland, pledging to bring forward legislation before the next general election.

He also said it would not be “the end of the world” if power-sharing at Stormont was not restored before Brexit, although that would probably require direct rule from Westminster – likely to anger nationalists.