Shaykh al-Islam al-Mujahid Sidi al-Haj Omar ibn Said al-Futi (d. 1279/1864) said in Kitab Rima'h al-Hizb al-Rahim ala Nuhur Hizb ar-Rajim (The Spears of the League of the Merciful thrown at the Necks of the League of the Accursed) on the issue of mentioning Al-Basmala (Bismillah ar-Rahman ar-Rahim; In the Name of Allah the Most Gracious the Ever Merciful) when reading the Quranic Chapter of Fatiha (Ch. 1): 

According to Lubab at Ta'wil, Shafi’a and a group of the scholars maintained that the Al-Basmala (Bismillah ar-Rahman ar-Rahim; In the Name of Allah the Most Gracious the Ever Merciful) is a verse of the Fatiha (Ch. 1), and of every verse, apart from the Verse of Mohammed (Ch. 47). This is the opinion of Ibn Abbas, Ibn Umar, Abu Haraira, Sa'id ibn Jubair, Ibn Al-Mubarak, Ahmad and Ishaq. Al-Baihaqi transmitted this opinion on the authority of Sidna Ali ibn Abu Talib, az Zuhri and Mohammed ibn Ka'b. Al-Awzai, Imam Malik, and Abu Hanifa maintained that the al-Basmala is not a verse of the Fatiha. Abu Dawud added: "Nor is it a verse of any other verse, and it is only a part of one verse of the verse of the Ant (Ch. 27). It is only inscribed at the beginning of the Verses for the purpose of marking the division between them and invoking Allah's blessing". Imam Malik said: "It should not be pronounced at the beginning of the prescribed ritual-prayer." Sayyida Aicha (may Allah be satisfied with her) is reported as having said: "The Holy Prophet (peace and blessing be upon him) used to begin the ritual-prayer with the takbir and Al-Hamdulillahi Rabbil al-Alamin." Some of the scholars have said: "The first revelation delivered by Gabriel was: Recite: In the Name of your Lord who created (96:1) and he did not mention the al-Basmala at the beginning of it, so this proves that it is not part of the chapter”. Besides, the Companions unanimously agreed on the number of verses in many of the verses, including thirty verses of Chapter al-Mulk (Ch. 67), three verses in the Chapter al-Kawthar (Ch. 108), and four verses in the Chapter al-Ikhlas (Ch. 112). If the al-Basmala had been part of each of those verses, the respective numbers would have been thirty one, four, and five."

As for the evidence provided by those who maintain the establishment of the al-Basmala at the beginning of the verses, on the basis of tradition, they cite the authentic report from Sayyida Umm Salama (may Allah be satisfied with her) who said, "The Prophet (peace and blessing be upon him) recited the al-Basmala at the beginning of the Fatiha in the ritual-prayer, and he considered it a verse thereof." Concerning the Saying of Almighty Allah [We have given you seven of the oft repeated (verses) and the mighty] (Quran 15:87), It is reported that Ibn Abbas said: "They are the Opening Verse of the Book." When he was asked: "So where is the seventh?," he replied: "Bismillah ar-Rahman ar-Rahim." As reported by Daraqutni on the authority of Abu Huraira, The Holy Prophet said: “When you recite "Al-Hamdulillah Rabbil Alamin," you must recite "Bismillahi Rahman Rahim" because it is the Mother of the Quran and the Mother of the Book. As for the seven oft repeated verses the Al-Basmala is one of them."

Sidi Mohammed al-Ghali Boutaleb (d. 1244/1829) instructed me (Shaykh Sidi al-Haj Omar ibn Said al-Futi), while we were in the City of al-Madinah, to recite the al-Basmala at the beginning of the Fatiha in the ritual-prayer and on other occasions. He authorized me to practice that myself and to pass it on. He was acting on the advice of our master and our means to access to our Lord, the Hidden Pole (al-Qutb al-Maktum) and the Sealed Isthmus (al-Barzakh al-Maktum), Sidna Shaykh Ahmed ibn Mohammed al-Hassani Tijani, for he had instructed him to act accordingly and he had received permission from the Chieftain of Existence, our master and our patron Sidna Mohammed (peace and blessing be upon him). Sidi Mohammed al-Ghali also told me, while we were in the City of Mecca, that I should recite the al-Basmala connected with the Fatiha in a single breath, in the ritual-prayer and on other occasions. He had received that advice from Sidna Shaykh Tijani. He also informed me of secrets related thereto, including those inscribed on a sheet of paper which he game me. The text of it reads as follows:

Shaykh Al-Qadi Majd ad Deen Al-Firuzabadi said: By Allah, the Almighty, Shaykh Safiyyu Deen Al-Ba'labakki informed me, on the authority of Shaykh Qaruni, that Shaykh Mohammed Ibn Arabi al Hatimi said:
When you recite the Fatiha, you must say: Bismillahi Rahman Rahim in a single breath, for I have this to tell you:
By Allah the Almighty, I heard from the mouth of Abu Bakr Al-Fudail ibn Mohammed Al-Katib:
By Allah the Almighty, I heard from the mouth of Abu Mohammed Ali Salisi:
By Allah the Almighty, Abdullah well known as Abu Nasr Sarkhawi informed me:
By Allah the Almighty Abu Abdullah Al-Warraq informed me:
By Allah the Almighty Mohammed ibn Yunus at Tawil informed me:
By Allah the Almighty Mohammed ibn Al-Husain Al-Alawi Zahid informed me:
By Allah the Almighty Abu Bakr Rajii informed me:
By Allah the Almighty Umar ibn Musa Al-Barmaki informed me:
By Allah the Almighty Anas ibn Malik informed me:
By Allah the Almighty Ali ibn Abi Talib informed me:
By Allah the Almighty Abu Bakr as Siddiq informed me:
By Allah the Almighty the Chosen One (Al-Mustafa) (saw) informed me:
By Allah the Almighty Gabriel (peace upon him) informed me:
By Allah the Almighty Michael (peace upon him) informed me:
By Allah the Almighty Israfil (peace upon him) informed me:

Allah said: "O Israfil, by My Might and My Majesty and My Magnanimity and My Noble Generosity, if someone recites [Bismillah ar-Rahman ar-Rahim] connected with the Fatiha (Ch. 1), one single time, bear witness that I have forgiven him, that I have accepted his good deeds, that I have pardoned his misdeeds, that I will not burn his tongue with the Fire, and that I will grant him refuge from the torment of the tomb, the torment of the Fire, the torment of the Day of Resurrection, and the greatest terror."