4. Submarine attacks by bombardment of Bahrein and Bushire; by torpedo attack on shipping in these ports and by minelaying in the Shatt-el-Arab and Khor Musa, is also possible; as is bombardment or a blocking operation by disguised merchant vessels. 5. In event of German invasion of Turkey or an advance into the Caucasus the whole area may be subject to a scale of attack by land based aircraft which may include minelaying in the waters of the Khor Muse and Shatt-el-Arab. Land attack may be expected to follow.