Marcus was born on 25 December 1911 in Bermondsey, Surrey to Romanian born Emmanuel and Australian born Rosie nee Black. Emmanuel became a naturalised British citizen in 1892 and worked as a draper and fancy goods dealer. Marcus qualified as a pharmacist and in 1939 he was living with his family at Marine Parade in Southend on Sea and he was listed as a chemist and a LAC at RAF Southend.

He was soon called up on 1 September 1939, and after completing his training he was commissioned as a pilot officer with 600 (County of London) Squadron on 2 February 1940. On 10 May 1940 Marcus was an air gunner on Blenheim L1517 which along with five other aircraft attacked the Waalhaven aerodrome at Rotterdam that had been captured by German paratroopers that morning. During the attack the sortie was attacked by Messerschmitt Bf 110’s, shooting down PO Haines plane, alongside four other planes. The crew evaded capture, making their way to The Hague, and from there to HMS Hereward and back to the UK. For his actions, PO Kramer was awarded the Distinguished Flying Cross (DFC), recommended on 15th May 1940, awarded on 9th July 1940. “Pilot Officers Kramer and Haines were air gunner and pilot in one of six aircraft attacking Rotterdam aerodrome on 10th May, 1940. Immediately after attacking aircraft on the ground, they were themselves attacked by six enemy fighters. The rear gun turret operating mechanism had been put out of action and the gun itself jammed but, in a most calm manner, Pilot Officer Kramer directed his pilot how best to evade the attacks of the enemy fighters and at the same time dismantled and repaired his gun. As the last enemy aircraft attacked, this officer had his gun working and succeeded in driving the enemy off. By the great coolness of Pilot Officer Kramer and the accurate information he gave, Pilot Officer Haine with great skill succeeded in bringing his badly damaged aircraft to a position where he was able to make a forced landing in friendly territory.”

Marcus was killed alongside his pilot William John Methven, 43349, on 21 May 1941 on board Tiger Moth N6853. The aircraft was seen to ditch in the River Severn, near Beachley, when it ran out of fuel in bad weather. Jewish Chaplains wrote to his father who replied that ‘his plane was seen to crash into the River Severn near Chepstow and his tunic was washed up almost immediately and is therefore believed to be dead’.