Thank you for joining me on this four-part history series about Tower Bridge. My name is David Laird and I work as an Education and Marketing Officer at Tower Bridge. 

Over the next four short episodes, I would like to share the history of London's Defining Landmark with you.

Today I will be describing the origins and initial design for Tower Bridge, with following episodes covering the ‘construction process’, ‘how and who lifts Tower Bridge’ and finally some ‘historic tales of this world-famous river crossing’. 

So before I start, I can imagine many of you will have passed over Tower Bridge by car, foot or bus. 

But I wonder how many of you have visited inside by climbing the 206 steps, or more likely have got the lift to the top?

For apart from being a working Bridge since 1894, Tower Bridge has been a popular tourist attraction since 1982, with our recent installation of a glass floor now bringing some 800,000 visitors inside each year. 

But the story of Tower Bridge is one of practicality, eccentricity, local connections and the preservation of a world-famous landmark.  

Now the origins of the Bridge's construction can be found in the decades and indeed centuries before its emergence out of the Thames. 

Since Roman times, the Thames has provided both a focal point of London life and the economic highway to the people and City of London. 

From the departure of the Romans in the 5^th century till the mid-18^th century, London flourished with only one bridge across the Thames – London Bridge.

Famed through nursery rhyme by children the nation over, it is sometimes confused with the tall granite and Portland stone heights of Tower Bridge. 

You see London Bridge – with its 2000-year story would provide the exclusive and only crossing point across the Thames for much of the city’s past.

But this began to change with the opening of Putney Bridge in 1729, followed by the London Bridges of Westminster, Blackfriars, Waterloo and Southwark.  

Regardless of these new crossings, by the mid-19^th century, London Bridge was still providing the principal route for those heading north and south each day. 

And to put it simply, this was a problem! 

By the late 19^th century, the population of London had at least doubled in size. 

Indeed, with the arrival of Queen Victoria on the throne, London began to sprawl, as the metropolis became transformed by steam power technologies and the innovations of the industrial revolution. 

Contemporary reports described London Bridge as “the only roadway crossing across the Thames for…a population of a million... about one third of the entire metropolitan population of London”.  

To put it into context, about a third of those living east of London Bridge had no adequate local crossing to use. 

I am sure you can imagine the chaos as horse-drawn vehicles, crowds of commuters and farmers bringing their livestock to market squeezed across London Bridge each day. 

In fact, it was often reported that trips across could take an individual up to two hours to complete - four hours everyday including the return leg.

With the dismissal of trying to enlarge the existing width of London Bridge, the creation of a new crossing became key. 

By the late 19^th century, both the Government and the City of London Corporation had received numerous petitions calling for a new crossing point to be established to the east of the Tower of London. 

This culminated on the 10^th February 1876 when the Corporation of London requested that the Bridge Houses Estates – this is the body that maintains the upkeep of the 5 City bridges of London – set up the Special Bridge or Subway Committee to consider the desirability of erecting a bridge or subway under the Thames east of London Bridge and determining the best means of carrying this out.

Now tunnelling had, by this stage, proved both an expensive and unpredictable business. The earlier Thames Tunnel linking Wapping to Rotherhithe, designed by Sir Marc Brunel and his son, assisted by the later famed Isambard Kingdom Brunel would close within only twenty years of construction. Intended to carry vehicles and pedestrians, a lack of funding left the structure ‘damp, stained and peeling’ – becoming a haven for undesirable and criminal elements. 

But by 1876, although some subterranean tunnels were proposed, the majority of those submitted were for a bridge crossing. The process to select the winning design was that of an informal competition, without a start or end date, engineers and architects began submitting their designs for the new crossing. In total roughly 50 different entries were received by the committee, with a number of high profile engineers taking part.

I am just going to explain a couple of those designs to you.

The first is by George Barclay Bruce’s, his so-called ‘rolling Bridge across the Thames’. This was ruled out for its operational impracticality, it did however keep to the brief, that at all times river shipping must still be able pass unimpeded. 

I should say that the proposed location for a new bridge crossing, was the ‘Pool of London’, a busy dock with close to 4,000 large ships requiring access each year. With this in mind, it was therefore essential that any new design included the functionality to keep what was at this time the busiest port in the world running.

The second design was by Frederic Barnet – he proposed this duplex bridge whereby both vehicle and river traffic could continue uninterrupted by the other. If you can imagine a giant figure-of-eight, looping it's way from  north to south across the Thames.

And, thirdly we have one of three designs proposed by Sir Joseph Bazalgette. Bazalgette who was famed for having earlier designed the London sewer network and subsequent creation of the London embankments. Here Bazalgette proposed a high-level single span bridge that would dwarf in height any shipping of the day and further requirement for a movable element. 

One such feature that may come as a surprise in these early submission for a new Tower Bridge is the lack of any Towers. 

The reason being that Tower Bridge today, as intended in 1876, was that the name reflected its position adjacent to the Tower of London rather than the design of the Bridge itself. 

As these designs were being submitted, so too was the eventual winner ‘Sir Horace Jones’ honing his submission.

Well folks, that’s the end of our origins and design episode, I will be back again soon to tell you more about the construction of Tower Bridge. Goodbye for now.