In AD 60, London was burnt to the ground by the forces of Queen Boudicca of the Iceni tribe (from modern Norfolk), when she led a major revolt against Roman rule. The governor, Suetonius Paulinus, who was busy exterminating the Druids in North Wales, marched his troops south in an attempt to save London but, seeing the size of Boudicca's approaching army, decided he could not mount an adequate defence and evacuated the city instead. Not everyone managed to escape though and many were massacred. Though the governors' military duties kept them mostly on the British frontier, it seems likely that they spent the winter months in London, the most convenient city from which to reach any part of Britain or the continental Empire. From the 250s, an altar inscription records that Governor Marcus Martiannius Pulcher rebuilt the Temple of Isis in the city; and a speculator, from his or a subsequent governor's staff, was buried on Ludgate Hill. An elaborate late 1st century building, with large reception rooms and offices, has been partially excavated beneath Cannon Street Station. It may have been the Governor's Palace. A second palatial building was recently discovered in the smaller trading settlement at Southwark, in the marshes south of the river.

The financial and economic equivalent of the governor was the procurator and there is clear evidence that the offices of this official lay somewhere within the city of Roman London. The Procurator, Gaius Julius Alpinus Classicianus who rebuilt the city after Boudicca's rebellion and promoted London trade, died and was buried there. Parts of his monumental tombstone have been dug-up and are on display in the British Museum.

Bricks and writing tablets have also been found stamped with such messages as 'issued by Imperial Procurators of the Province of Britain'.

The major symbol of Roman rule was the Temple of the Imperial Cult. Emperor worship was administered by the Provincial Council whose headquarters appear to have been in London by AD 100. A member of its staff, named Anencletus, buried his wife on Ludgate Hill around this time. Pagan worship flourished within the cosmopolitan city. A temple to the mysterious Eastern god, Mithras, was found at Bucklersbury House and is displayed nearby. Traditionally, St. Paul's stands on the site of a Temple of Diana. Other significant buildings also began to appear in the late 1st century, at a time when the city was expanding rapidly. The forum (market-place) and basilica (law-courts) complex, at Leadenhall Market, was erected and then quickly replanned as the largest such complex north of Alps. The forum was much bigger than today's Trafalgar Square. Procurator Agricola encouraged the use of Bath Houses and a grand public suite has been excavated in Upper Thames Street. They were as much a social venue as a place to bathe. There was a smaller version at Cheapside and, in later centuries, private bath houses were also built. Another popular attraction was the wooden amphitheatre erected on the north-western outskirts of the city. It is possible that gladiatorial shows were put on here, though lesser public sports, like bear-baiting, may have been more regular.

By the early 2nd century, London had spread west of the Walbrook and a military fort was erected near the amphitheatre which itself was rebuilt in stone. This may have been in anticipation of a visit from the Emperor Hadrian in AD 122. He would not have approved of soldiers being billeted with civilians. The garrison was probably modest with responsibilities restricted to ceremonial, escort and guard duties. The amphitheatre may have been used for their military exercises. By about AD 200, the administration of Britain was divided in two. York became the capital of Britannia Inferior & London of Britannia Superior. Around the same time the city also acquired its famous walls (probably about 20ft high). This protective measure may have been due to Civil War, initiated when Governor Clodius Albinus tried to claim the Imperial Crown in Rome.

A century later, the Emperor Diocletian again reorganised Britain to improve administrative efficiency. London became the capital of Maxima Caesariensis, one of the four newly created provinces. It remained the financial centre of Britain, home of the treasury, and the usurping British Emperor Carausius established a mint there in AD 288. Carausius was soon murdered by his finance minister, Allectus. The latter employed Frankish mercenaries who besieged London and then proceeded to plunder it. Just in time, the true Emperor's general, Constantius Chlous, arrived, with a fleet of ships, to save the city & reunite Britain with Rome.

Details of late Roman London, and Britain as a whole, are few. Christianity appears to have reached the province at an early date and, only a year after the religion became officially tolerated in the Empire, London had its own Bishop, Restitutus, who is known to have attended the Imperial Council of Arles. Less welcome newcomers may have led to the addition of catapult towers along the city defences around AD 350. Picts and Irishmen were certainly invading Southern Britain eighteen years later. The Emperor Julian sent his general Theodosius to expel them and he used London as his headquarters. Soon afterward, the city's prestige was increased by its renaming as Augusta. Another British usurper, Magnus Maximus, claimed the Western Imperial throne in AD 383. He is also known to have set up a mint in London and it was probably from the city that he left, with much of the Roman army stationed in Britain, for his lengthy campaigns on the Continent. Five years later, Maximus was dead and Imperial power was waning in the extreme Western provinces. Germanic style buckles, of circa AD 400, found in the city indicate that, as in other British towns, London officials were employing Saxon Mercenaries. London was arranging its own defence and, only ten years later, the Emperor Honorius renounced his responsibility for the British Provinces.