Some expcerpts. The whole article, "THE ACCESSION OF KALAT: MYTH AND REALITY" is well worth the read:
A series of meetings between the Viceroy, as the Crown’s Representative, the Quaid and the Khan of Kalat followed, which resulted in a communiquéй on August 11, 1947. The communiquй stated that:a. The Government of Pakistan recognizes Kalat as an independent sovereign state in treaty relations with the British Government with a status different from that of Indian States.
b. Legal opinion will be sought as to whether or not agreements of leases will be inherited by the Pakistan Government.
c. Meanwhile, a Standstill Agreement has been made between Pakistan and Kalat.
d. Discussions will take place between Pakistan and Kalat at Karachi at an early date with a view to reaching decisions on Defence, External Affairs and Communications.
On March 18, 1948, the Ministry of Foreign Affairs of Pakistan issued a press note that the States of Kharan, Las Bela and Mekran had applied for accession to Pakistan, which was granted to them. The press report also said that after the accession of these three states to Pakistan, Kalat’s territory had been reduced to half of its previous area, and had ceased to have any outlet to the sea.54 The UK High Commissioner in Pakistan reported that the offer of accession was accepted by the Pakistan Cabinet when Jam of Las Bela, Chief of Kharan and Nawab Bai Khan of Mekran met the Quaid on March 17, 1948 and told him that “if Pakistan was not prepared to accept their offers of accession immediately, they would be compelled to take other steps for their protection against Khan of Kalat’s aggressive actions.”55 This was seen as a blow to the Khan as head of the Confederacy, the Baluchistan States Union.
As this account makes amply clear, the story of the accession of Kalat was a long drawn out process. And although Pakistan came into being on August 14, 1947, the accession of Kalat did not take place till March 27, 1948. The three feudatories, two of which Las Bela and Kharan, which were recognized by the British as independent, played a key role in forcing the Khan of Kalat to accede to Pakistan.
The issue of the accession of Kalat has been clouded in controversy and mythology, because little or no research has been done on the subject. One scholar has described the annexation as, “a nine month tug of war that came to a climax in the forcible annexation of Kalat.”60 The reality is quite different. Khan of Kalat had no choice but to accede after Kharan, Las Bela and Mekran’s acceded to Pakistan, cutting off Kalat from the sea. The announcement on All India Radio that Kalat had been negotiating with India, which Nehru was at pains to deny in the Indian Parliament, caused such an outcry within Baluchistan and outside that the Khan acceded immediately to Pakistan.