(f) In the matter of submarines, however, Germany, while not exceeding the ratio of 35:100 in respect of total tonnage, shall have the right to possess a submarine tonnage equal to the total submarine tonnage possessed by the Members of the British Commonwealth of Nations. The German Government, however, undertake that, except in the circumstances indicated in the immediately following sentence, Germany's submarine tonnage shall not exceed 45 percent. of the total of that possessed by the Members of the British Commonwealth of Nations. The German Government reserve the right, in the event of a situation arising, which in their opinion, makes it necessary for Germany to avail herself of her right to a percentage of submarine tonnage exceeding the 45 per cent. above mentioned, to give notice this effect to His Majesty's Government in the United Kingdom, and agree that the matter shall be the subject of friendly discussion before the German Government exercise that right.