In the context of The Great Game, the Anglo–Russian contest for influence in Central Asia, the British wished Afghanistan to remain an independent country with friendly relation as a buffer state against Russian expansion towards India.

Separate from and preceding the dispute over Herat, was an incident concerning Mirza Hashem Khan, whom the British ambassador had hoped to appoint as a secretary to the mission in Tehran.

[3] The Iranian army that fought against the British expeditionary force at the Battle of Khoshab was commanded by General (Amir-Nuyan) Mehr Ali Khan Nuri Shoja ol-Molk.

In the aftermath of the disastrous First Anglo-Afghan War, the British Government were reluctant to send a force overland to relieve Herat directly, and so decided instead to attack the Persian Gulf coast.

They ordered the government in India to launch a maritime expeditionary force to attack the general area of Bushehr, the primary port of entry into Iran at the time.

[8] Initially a division, under Major General Foster Stalker, was organised comprising 2,300 British soldiers and 3,400 Indian sepoys of the Bombay Presidency army which landed in Iran in early December 1856.

They stormed the old fort at Reshire (also called Rishahr or Rashir) and after a short naval bombardment went on to capture the city on 10 December, ably assisted by the two companies of Bombay Sappers & Miners.

[14] In hoping for a diplomatic solution by Farrokh Khan’s embassy at Constantinople, Nuri's government claimed to have directed all authorities on Iran's southern frontier to not make any preparation for war.

The British invasion force that was to be dispatched to the Persian Gulf in an effort to intimidate the Iranian government from further pressing its claim to Herat was eventually divided into two divisions.

[21] The Iranian army under command of Gen. (Amir-Nuyan) Mehr Ali Khan Shoja ol-Molk was misinformed by his reconnaissance units that the British were advancing with 13,000 infantry, 1,000 cavalry, and 28 guns.

The Iranian justification for the hasty withdrawal was to prevent high casualties from the overestimated size of the British forces and the expected explosion of the unsecured ammunition stored at Borazjan.

Outram's sense of urgency in his letter to the Governor-General of India dated 14 February 1857 was visible through his concern for the prospective loss of Bushehr should Iran raise a larger than expected army.

On 14 Jumada l-Ula, Reza Qoli Khan left the Iranian encampment with a contingent of 400 from the 1st Arab Regiment and 2 field guns to gather additional rations and supplies for the province's defense.

The Chief of his staff, Colonel Lugard took command of the British forces and quietly covered the mishap, ensuring few others knew of Outram's condition until the next morning.

As the British lines advanced, Hunt and Townsend cite few casualties among the Highlanders and 26th Native Infantry but note that the first brigade, first division fared worse against the Iranian bombardment.

The British focus on the Iranian left flank managed to push back the cavalry under Sohrab Khan, which eventually retired to the Haj Mollah Pass, 7 miles away from the battlefield.

[41] Under musket and cannon fire, the 1st Qashqai Regiment of Fars entered an infantry square formation with kneeling ranks and sustained the charge of the 3rd Cavalry.

Two Victoria Crosses were awarded to the Commander's Adjutant Lieutenant Arthur Thomas Moore for first breaking into the square, and Captain John Grant Malcolmson.

The British army resumed its march back to Bushehr but in deplorable conditions; torrential rains created mud deep enough to pull a man's boots from his feet.

In his correspondence with Governor-General Canning, Outram reported that the total size of the new forces raised between Shiraz and Khesht for Mirza Mohammad Khan's army was 27,800 men with 85 guns.

[61] Mohammad Khan had made his way to Farashband with his troops and had ordered several contingents to rendezvous at Nanizak by 6 March to form a larger army fit to assault Bushehr.

[62] The British then shifted their focus north up the Persian Gulf, invading Southern Mesopotamia by advancing up the Shatt al-Arab waterway to Mohammerah at its junction with the Karun River, short of Basra.

The troops that would stay in the encampment included two field batteries, the mountain-train, the entire cavalry of the first division, three companies from her Majesty's 64th and the 78th Highlanders, the 4th rifles, 20th Native Infantry, and the Belooch battalion.

[67] The British army would counter the Iranian bombardment with the broadsides of the Clive and Falkland sloops as well as the Ajdaha, Feroze, Semiramis, Victoria, and Assaye steamers.

[68] One of the superior officer's of Khanlar Mirza's army held a military inspection of 3,000 infantry in sight of the British ships near the coast as a show of force.

[69] The British troops were also made aware of a considerable detachment of irregular cavalry and infantry occupying the village of Mahamur, where pickets had been constructed along some ruined buildings.

[3] Watson likewise cites the suicide as stemming from the unbearable responsibility of defending Bushehr against the growing southern Iranian army of Mirza Mohammad Khan.

[82] As the Iranian batteries fell silent, the brigadiers of their army, which was situated behind the fortifications, retreated while the British troops were called to halt to properly arrange their lines.

News of the onset of fighting resulted in a formal rupture of talks, but discussions soon began again in Paris, and both sides signed a peace treaty on 4 March in which the Shah agreed to withdraw from Herat and to refrain from further interference in the affairs of Afghanistan.

The Poona Horse carries a Standard surmounted by a silver hand and bearing a Persian inscription captured at Koosh-Ab, in commemoration of the brilliant charge of the 3rd Bombay Light Cavalry which broke into enemy infantry and decided the fate of the day.