Polish unit at Salon and Clermont-Aulnat (now Clermont-Ferrand Auvergne Airport) operated the equally inadequate Koolhoven F.K.58 from 30 May commanded by Captain Walerian Jasionowski. The Polish Air Force in France had 86 aircraft with one and a half of the squadrons fully operational, and the remaining two and a half in various stages of training. Altogether, the Polish pilots flew 714 sorties during the Battle of France. According to Jerzy Cynk, they shot down 51.9 enemy planes (summing fraction kills – 57 kills including 16 shared victories), in addition to 3 unconfirmed kills and 6 3/5 damaged. According to Bartłomiej Belcarz they shot down 53 aircraft, including 19 kills shared with the French. These 53 victories makes 8% of 693 allied air victories in the French campaign. At the same time they lost 44 planes (in combat, accidents and on the ground) and lost 8 fighter pilots in combat, 1 missing, and 4 in accidents. In Britain After the collapse of France in 1940, a large part of the Polish Air Force contingent was withdrawn to the United Kingdom. However, the RAF Air Staff were not willing to accept the independence and sovereignty of Polish forces. Air Marshal Sir Hugh Dowding later admitted he had been "a little doubtful" at first about the Polish airmen. The British government informed General Sikorski that at the end of the war, Poland would be charged for all costs involved in maintaining Polish forces in Britain. Initial plans for the airmen greatly disappointed them: they would only be allowed to join the Royal Air Force Volunteer Reserve, wear British uniforms, fly British flags and be required to take two oaths, one to the Polish government and the other to George VI; each officer was required to have a British counterpart, and all Polish pilots were to begin with the rank of "pilot officer", the lowest rank for a commissioned officer in the RAF. Only after posting would anyone be promoted to a higher grade. Because of this, the majority of highly experienced Polish pilots had to wait in training centres, learning English Command procedures and language, while the RAF suffered heavy losses due to lack of experienced pilots. On June 11, 1940, a preliminary agreement was signed by the Polish and British governments and soon the British authorities finally allowed for the creation of two bomber squadrons and a training centre as part of