Why the Great Fire of London matters to you today
Writer Tom Bradby had a lot of ground to cover when he wrote ITV’s four-part drama about the Great Fire of London, so it’s perhaps understandable that he misses out what might reasonably be called trivial post-fire details.

But they matter to you, even today, because the fire that destroyed a great swathe of 17th-century London led directly to some of the simplest and most effective passive fire protection technology ever invented.

You’ve never been instructed in its use – and never need to be. It’s quite possible that you own some, work near some, or see some every day. They are window sills and inset windows.

You can be forgiven for raising a disbelieving eyebrow at this point, but it’s a fact. Historian Harry Mount draws attention to them in his book ‘A Lust For Windowsills’. The book itself is an entertaining look at what buildings can tell us about themselves from the style of architecture to the materials used.

Back to those window sills… The Great Fire tore through London with terrifying and bewildering speed in September 1666 because there was so much available fuel. Most of the buildings were of timber, and Tudor houses overhung the streets, with their windows flush with the front of them. As Harry Mount says: “…pre-1666 London was one endlessly overlapping line of highly flammable dominoes. Torch a bakery in Pudding Lane and you torched 13,500 houses, 87 churches, 44 guild halls, the Royal Exchange and St Paul’s Cathedral.”

The rebuilt city benefitted from two pieces of fireproofing legislation. The first, in 1709, saw the introduction of sills four or more inches deep and required windows to be set back from the front of the wall; the second, in 1754, meant that the outer timbers of sash windows had to be concealed behind brickwork.
The result was that a fire on a lower floor was prevented from spreading to the upper floors via the windows because the timber there was just that little bit out of the reach of the flames, and the sill presented a barrier to the flames getting up there anyway.

This London building shows the substantial window sills and inset, concealed-frame windows created by laws introduced after the Great Fire of London.

This first-ever film of The Great Fire of London has been made with a second great fire, which has involved burning down the set, as Tom Bradby, ITN’s Political Editor, explains: “Fire, it turns out, doesn’t look good in CGI, so we had to build a replica of Seventeenth Century London and then burn it down, child actors and all. Our Producer Gina Cronk is currently in The Priory. No, obviously that’s a joke, but it’s true to say that Towering Inferno II is unlikely to be her next project. Director Jon Jones did an amazing job. He was particularly keen to get the actors right into the fire, so any realism is purely intentional.”

Executive Producer Douglas Rae said: “We actually have the fire, smoke and cinders right there in front of the cameras with the actors. Some of the sets were built with fire bars and gas pipes running through them, and we had a big control panel like a spaceship to choose exactly where would go up in flames. You get a whoosh of flames. Then right at the end of filming we burned the whole set down with several cameras running and lots of fingers crossed.”

The first episode of The Great Fire is screened on ITV at 9pm on Thursday October 16th.