This was British special forces operation to parachute a four-man Special Operations Executive team into German-occupied Yugoslavia (20 September 1941).
After the April 1941 German occupation of Yugoslavia following the 'Unternehmen 25' invasion, the SOE began to collaborate with local royalist and communist resistance groups about how to continue the fight against the Germans. One specific group of British interest was the Četnik royalist guerrilla movement led by Pukovnik Dragoljub 'Draža' Mihailović , and it was decided that a lison mission would be sent to him and that this would be followed by air drops to supply his forces.
The effort began with the 'Bullseye' mission, in which Captain D. T. Hudson, Major Zaharije Ostojević and Major Mirko Lalativić (both representatives of the Yugoslav government-in-exile in London) were landed at Petrovec on the Monenegrin coast from the British submarine Triumph on 20 September 1941. The mission initially established contact with the communist partisan movement led by Josip Broz Tito, but then moved on to reach the Četnik headquarters. Here Ostojević and Lalativić joined the Četnik movement, in the process abandoning Hudson. The SOE thus lost with Hudson until April 1942.
As Yugoslavia was too far distant to be reached by supply-dropping aircraft operating from the UK, the choice was made to base two converted Armstrong Whitworth Whitley bombers of No. 138 Squadron on Malta for 'Bullseye'. One of the aircraft was flown by Flight Lieutenant John Austin, who flew the first supply drop on the night of 7/8 November 1941. For this mission the Whitley’s crew was supplemented by a Serb navigator to assist with map reading. The aeroplane flew north along the Adriatic Sea and then headed east across the Yugoslav coast to the drop zone at Mitrovica. After receiving the prearranged signal Austin made several circuits to drop his containers before heading back to Malta. A second supply attempt had to be cancelled a month later as a result of adverse weather conditions over the drop zone.
On 3 February 1942 Austin made an 11-hour round trip to drop four agents and eight containers of supplies near Sarajevo. Austin flew at just 700 ft (215 m) to drop the containers and two of the agents before making a second circuit to drop the other agents.