Robert Mylne (4 January 1733 – 5 May 1811) was a Scottish architect and civil engineer, particularly remembered for his design for Blackfriars Bridge in London.

As his career progressed, he concentrated more on engineering, writing reports on harbours and advising on canals, and appearing as an expert witness in lawsuits and trials.

He was also a founder of the Architects' Club, another early professional body, and regularly socialised with the eminent doctors, philosophers and scientists of his day.

[3] In autumn 1754, Mylne set off for mainland Europe on the "Grand Tour", to join his brother William, who had been studying in Paris for a year.

They made contact with Andrew Lumisden, secretary to James Stuart, the "Old Pretender",[4] and Abbé Peter Grant, the Scots agent in Rome.

[6] A letter from the Duke of Atholl enquired when he would return to resume work at Blair, and offered Mylne the post of head carver, but he preferred to continue with his studies.

[7] In the spring of 1757, shortly after William had returned home, Mylne accompanied the diplomat Richard Phelps and antiquarian Matthew Nulty on a tour of Sicily.

[8] In 1758, Mylne decided to enter the triennial architecture competition, known as the Concorso Clementino,[9] at the Accademia di San Luca (St Luke's Academy), the subject being a design for a public gallery.

[10] Mylne left Rome in April 1759, travelling to Florence, where he was elected to the Academy of Art, then Venice, Brescia, and villas designed by Andrea Palladio.

The closing date for the design competition was set for 4 October, giving Mylne less than three months to complete his scheme, although in his favour, he apparently found a friend in John Paterson, secretary of the Bridge Committee, and a fellow Scot.

This departure, as yet untried in Britain, provoked a public debate, and brought Mylne under attack from Dr Samuel Johnson, a friend of John Gwynn, who suggested that elliptical arches would be too weak.

[12] On 22 February 1760, Mylne was finally declared the winner of the competition, and he was appointed surveyor to the new Blackfriars Bridge, with overall responsibility for design, construction and future maintenance of the structure, on a salary of £400 a year.

Mylne introduced several technical innovations, including the use of removable wedges in the centring which supported the arches during construction, making it easier to dismantle.

[16] Although Mylne was briefly the target of satirical anti-Scots cartoons and pamphlets at the time of winning the competition,[17] the completed bridge was universally well-received, and tolls repaid the £152,840 cost of building within a few years.

[25] Mylne's design for the City of London Lying-in Hospital, built 1770–1773, comprised a high central cupola flanked by pedimented blocks.

Mylne's first work at Kings Weston House was in 1763 and involved designing and extensive new stables and kitchen garden complex which still remain.

In the years following Mylne worked on extensively modernising Kings Weston House and replacing Sir John Vanbrugh's austere interiors.

In 1766, Mylne was appointed Surveyor to St Paul's Cathedral, completed by Sir Christopher Wren some 55 years earlier.

The existing Latin epitaph, Lector, si monumentum requiris, circumspice (reader, if you seek his monument, look around you), was re-used on a tablet mounted on the organ screen in 1810, although this was destroyed in the Blitz.

[33] A fire the following January destroyed the chapel, but Mylne and his superior, James Stuart, failed to work together to design and build a replacement.

[36][39] Robert had been intended as his father's successor, but his established position in London meant that his younger brother William took on the family business on Thomas Mylne's death in February 1763.

Robert was one of his brother's financial guarantors, and was involved in the subsequent problems for several years, until William, his architectural career over, fled to America in 1773.

The couple resided at the Water House, New River Head, and had nine children: Mary Mylne died of a lung complaint in July 1797, shortly after the family had moved to Great Amwell.