quality:corruption
Siege of Arcot

In the summer of 1751, Chanda Sahib left Arcot to besiege Muhammed Ali Khan Wallajah at Trichinopoly. This placed the British at Madras in a precarious position, since the latter was the last of their major allies in the area. The British company's military was also in some disarray, as Stringer Lawrence had returned to England in 1750 over a pay dispute, and much of the company was apathetic about the dangers the expanding French influence and declining British influence posed. The weakness of the British military command was exposed when a force was sent from Madras to support Muhammad Ali at Trichinopoly, but its commander, a Swiss mercenary, refused to attack an outpost at Valikondapuram. Clive, who accompanied the force as commissary, was outraged at the decision to abandon the siege. He rode to Cuddalore, and offered his services to lead an attack on Arcot if he was given a captain's commission, arguing this would force Chanda Sahib to either abandon the siege of Trichinopoly or significantly reduce the force there.

Madras and Fort St. David could supply him with only 200 Europeans, 300 sepoys, and three small cannons; furthermore, of the eight officers who led them, four were civilians like Clive, and six had never been in action. Clive, hoping to surprise the small garrison at Arcot, made a series of forced marches, including some under extremely rainy conditions. Although he did fail to achieve surprise, the garrison, hearing of the march being made under such arduous conditions, opted to abandon the fort and town; Clive occupied Arcot without firing a shot.

The fort was a rambling structure with a dilapidated wall a mile long (too long for his small force to effectively man), and it was surrounded by the densely packed housing of the town. Its moat was shallow or dry, and some of its towers were insufficiently strong to use as artillery mounts. Clive did the best he could to prepare for the onslaught he expected. He made a foray against the fort's former garrison, encamped a few miles away, which had no significant effect. When the former garrison was reinforced by 2,000 men Chanda Sahib sent from Trichinopoly it reoccupied the town on 15 September. That night Clive led most of his force out of the fort and launched a surprise attack on the besiegers. Because of the darkness, the besiegers had no idea how large Clive's force was, and they fled in panic.

The next day Clive learned that heavy guns he had requested from Madras were approaching, so he sent most of his garrison out to escort them into the fort. That night the besiegers, who had spotted the movement, launched an attack on the fort. With only 70 men in the fort, Clive once again was able to disguise his small numbers, and sowed sufficient confusion against his enemies that multiple assaults against the fort were successfully repulsed. That morning the guns arrived, and Chanda Sahib's men again retreated.

Over the next week Clive and his men worked feverishly to improve the defences, aware that another 4,000 men, led by Chanda Sahib's son Raza Sahib and accompanied by a small contingent of French troops, was on its way. (Most of these troops came from Pondicherry, not Trichinopoly, and thus did not have the effect Clive desired of raising that siege.) Clive was forced to reduce his garrison to about 300 men, sending the rest of his force to Madras in case the enemy army decided to go there instead. Raza Sahib arrived at Arcot, and on 23 September occupied the town. That night Clive launched a daring attack against the French artillery, seeking to capture their guns. The attack very nearly succeeded in its object, but was reversed when enemy sniper fire tore into the small British force. Clive himself was targeted on more than one occasion; one man pulled him down and was shot dead. The affair was a serious blow: 15 of Clive's men were killed, and another 15 wounded.

Over the next month the besiegers slowly tightened their grips on the fort. Clive's men were subjected to frequent sniper attacks and disease, lowering the garrison size to 200. He was heartened to learn that some 6,000 Maratha forces had been convinced to come to his relief, but that they were awaiting payment before proceeding. The approach of this force prompted Raza Sahib to demand Clive's surrender; Clive's response was an immediate rejection, and he further insulted Raza Sahib by suggesting that he should reconsider sending his rabble of troops against a British-held position. The siege finally reached critical when Raza Sahib launched an all-out assault against the fort on 14 November. Clive's small force maintained its composure, and established killing fields outside the walls of the fort where the attackers sought to gain entry. Several hundred attackers were killed and many more wounded, while Clive's small force suffered only four British and two sepoy casualties.

The historian Thomas Babington Macaulay wrote a century later of the siege:

... the commander who had to conduct the defence... was a young man of five and twenty, who had been bred as a book-keeper... Clive... had made his arrangements, and, exhausted by fatigue, had thrown himself on his bed. He was awakened by the alarm, and was instantly at his post... After three desperate onsets, the besiegers retired behind the ditch. The struggle lasted about an hour... the garrison lost only five or six men.

His conduct during the siege made Clive famous in Europe. The Prime Minister William Pitt the Elder described Clive, who had received no formal military training whatsoever, as the "heaven-born general", endorsing the generous appreciation of his early commander, Major Lawrence. The Court of Directors of the East India Company voted him a sword worth £700, which he refused to receive unless Lawrence was similarly honoured.

Clive and Major Lawrence were able to bring the campaign to a successful conclusion. In 1754, the first of the provisional Carnatic treaties was signed between Thomas Saunders, the Company president at Madras, and Charles Godeheu, the French commander who displaced Dupleix. Mohammed Ali Khan Wallajah was recognised as Nawab, and both nations agreed to equalise their possessions. When war again broke out in 1756, during Clive's absence in Bengal, the French obtained successes in the northern districts, and it was Mohammed Ali Khan Wallajah's efforts which drove them from their settlements. The Treaty of Paris (1763) formally confirmed Mohammed Ali Khan Wallajah as Nawab of the Carnatic. It was a result of this action and the increased British influence that in 1765 a firman (decree) came from the Emperor of Delhi, recognising the British possessions in southern India.

Margaret Maskelyne had set out to find Clive who reportedly had fallen in love with her portrait. When she arrived Clive was a national hero. They were married at St. Mary's Church in (then) Madras on 18 February 1753. They then returned to England.

Clive also briefly sat as Member of Parliament for the Cornwall rotten borough of St Michael's, which then returned two Members, from 1754 to 1755. He and his colleague, John Stephenson were later unseated by petition of their defeated opponents, Richard Hussey and Simon Luttrell.