London now has many bridges across the Thames but until the mid-18th century there was only one: London Bridge. It was always congested and took time to cross. The bridge was owned by the powerful City of London Corporation, which earned income from its tolls, so for centuries they blocked any ideas for a second crossing.

People could cross the river here at Westminster using a ferry, with the Archbishop of Canterbury profiting from its tolls. Yet, as the population and traffic increased, that became a great inconvenience to people, including aristocrats and government officials passing to and from the Palace of Westminster. It was the Earl of Pembroke who finally persuaded Parliament in 1736 that a bridge was required at Westminster. Of course, substantial compensation had to be paid to the Archbishop for the loss of his income.

There hadn’t been a bridge built over the Thames for 500 years, so no British engineer had the necessary experience. A Swiss architect was hired to design the new Westminster Bridge. It was built of stone and eventually took 12 years to construct and five times the original budget. Yet when completed it was hailed as extraordinary and something to be admired, becoming one of the capital’s tourist attractions. Artists, including Canaletto, came to create paintings of the new bridge.

The original Westminster Bridge lasted until the 1850s but by then it was suffering from structural problems and was replaced by the current cast-iron bridge, which was completed in 1862.