Although referred to as 'The Twins' within SOE, there was a substantial age difference between the Newton brothers: Henry was born in 1903 in Jerez, while Alfred was born 11 years later, in Valencia. Their British parents were variety artists, a profession which their sons also took up, becoming known as the Boorn Brothers (Boorn being their mother's maiden name). Basing themselves in Paris in 1924, they performed in music halls across Europe and South America. Henry married a French girl, Marcelle Dusseret, in 1929, and Alfred a German dancer, Theodosia Schmidt, in 1932, by whom he had three sons.

In 1939 the brothers became despatch riders for a French organisation, then travelled south when the Germans approached Paris. They were taken in by farm owners in the Dordogne, but continued trouble with the Vichy authorities put Alfred and Henry in prison in June 1941. Through the American consul the family obtained visas to leave France for Lisbon, while the brothers escaped one night, and with the help of their hosts managed to cross the Pyrenees into Spain. Immediately arrested as illegal immigrants, they were held in prisons at Figueras, Barcelona and Zaragoza, then sent to the concentration camp at Miranda, but were finally passed to the British in December. They were relieved to be on their way to Gibraltar, but the embassy had tragic news waiting for them: the SS Avoceta, which their parents and families had boarded at Lisbon, had been torpedoed on its way to Liverpool and all of them had been killed.

After arriving at Liverpool, MI 5 soon brought them to the attention of SOE, which interviewed them immediately. Determined to fight back however they could, Alfred and Henry were accepted by F Section and threw themselves into their training, impatient to return to France at the earliest opportunity. At the end of June they were granted their wish and flew out on the same flight as wireless operator Brian Stonehouse, parachuting near Tours, but it took two weeks of searching before they met their organiser Philippe de Vomécourt. What made it worse was that their efforts had been almost completely wasted: wireless operators were invaluable and Stonehouse could be used to call in badly needed supplies from London, but de Vomécourt had been unimpressed by the efforts of previous so-called weapons experts, and refused to take responsibility for the Newtons' welfare. They were sent on to Lyon, where despite uneasy relations with de Vomécourt's contacts they began to establish the GREENHEART circuit, which was composed of about 200 men in the Puy de Dôme area of southern France, but with very limited resources they eventually decided to abandon it and leave using an escape line into Spain. Unfortunately they were given away by an informer, and fifteen Gestapo agents burst into their safe house in Lyon just as they were planning to leave, on 4 April 1943. According to Alfred's later report, the room they were in was too small to allow them to fire at their attackers, but they managed to fight them off with their fists for five minutes before being overpowered.

Brutally tortured by the infamous Gestapo chief Klaus Barbie, they did not give any important information away, though Alfred made an unsuccessful escape attempt, throwing himself from a third floor window. They were transferred to Fresnes prison the following month, and were questioned at Avenue Foch but both continued to remain silent. In January 1944 they were deported to Buchenwald concentration camp along with F Section agents Christopher Burney and Maurice Pertschuk.

Put to work lifting stones in the quarry, then digging trenches through the bitter winter months, the Newton brothers were soon physically worn down, and Henry was sent to the hospital with double pneumonia. After his recovery he was able to find a job in one of the blocks, while Alfred worked from June 1944 in the Effektenkammer, the storehouse for prisoners' belongings. In March 1945 Pertschuk was executed by the SS, which prompted the brothers to hide in the Little Camp with Christopher Burney and Maurice Southgate, who had arrived in August. By repeatedly changing their prison numbers they were able to avoid detection, and on 11 April they were liberated by American forces. They arrived back in London a week later.

For their services, Henry and Alfred each received the MBE, and an account of their experiences, No Banners, by Jack Thomas, was published in 1955. Although both took up employment after the war - including running the Red Tape nightclub in Hanley, in partnership with fellow ex-agent John Starr - the cumulative effect of their wartime experiences had major consequences on their later lives; Henry had been granted a full disability pension at the end of the war and Alfred also suffered numerous medical problems in later life. After spending time in New Zealand, France and Spain, Alfred returned to England, where he died in July 1979. Henry died in Alicante, Spain in January 1980.