unassuming building. But this building had a remarkable

impact on England's industrial history.

Originally built in the 1720s, Derwentcote Steel Furnace

played an important role in the creation of steel

allowing for a huge step forwards in engineering and production.

I'm Rob Bell, engineer and adventurer

and I'm travelling around England, seeking out some of the key sites in

this country's shift towards a more modern way of manufacturing and living

This steel furnace employed an

early method of turning wrought iron into steel

and was active for over a hundred years up until the late 1800s.

To find out more about the part Derwentcote played

I'm meeting Mark Douglas, Senior Properties Curator

from English Heritage

- Mark, nice to meet you - You too

There's so much more to this building once you step inside

- Yeah, it's good isn't it - It's fantastic

So, tell me when was this steel furnace operational? When was it active?

It was active from the early part of the 18th century

We know probably from around about 1720.

This is the earliest surviving example of a cementation furnace in the country.

That's what makes it incredibly important

Can you tell me a bit about the process

of what went on in the furnace here - how you turn iron into steel?

The main principle is you must not let air get to the iron because it oxidizes it

So inside this massive masonry that you can see in front of you here, there's two chests

In those two chests they would pack bars of iron between layers of charcoal

and then top the whole thing off with sand to make it airtight

and light a fire. There's flumes going around the outside

up to a dome ceiling and flumes going underneath these two stone chests

And basically heat them up to about 1100 degrees

and keep it at that temperature for between seven and ten days

Then allow the whole thing to slowly cool down, probably another two weeks

During that process the iron inside there

will absorb the carbon out of the surrounding charcoal and that would then

create what we call blister steel. The whole surface would look like a

pancake or blistered up like a pancake when it came out of these furnaces

and that would be then used to forge

sheer steel and used to make the tools down in the forge

What kinds of tools, what kind of implements

might have been manufactured from the steel from this furnace?

Anything with edges. Anything with cutting edges

because it would hold an edge and it could be made a lot thinner

Scythes, shears and also swords

And was this part of England then intrinsically linked to steel production

and if so why was that?

Steel production in itself isn't really intrinsically linked to any particular place

It can be done anywhere, all you need is raw materials

What made this place important is geology and geography

Geology in the sense that we have access to raw materials such as iron

But the main thing that made this

different was the route between here and the continent

Between here and Sweden - the access to Swedish bar iron which is

an incredibly pure form of iron

So it was Swedish iron that was used

and turned into steel here, not English iron?

No, the British iron from around here was high in phosphorus

Swedish iron was incredibly pure

How important was Derwentcote then within the steel production of the

greater area of the North East?

Derwentcote was one of many many manufacturers around here

but it was the development of this

sort of process that lasted a long time at Derwentcote

But the valley itself, the Derwent valley, at one point was the biggest iron works in Europe

Over 50 percent of all the iron produced in the country in the 18th century

was produced in this valley. It was just a hotbed of furnaces

and steam and iron and smoke

It would have been an incredible place to be

Absolutely yeah it's very hard to

imagine that when you're walking around here now

Were there other furnaces similar to this in other parts of the country?

Sheffield is the main protagonist but somebody - probably a disgruntled employee

snuck off down to Sheffield and took the ideas

It wasn't the process itself, it was the technical bits in between that made the difference

The people move to where the opportunities lay.

It's an evolutionary process in a way

The process of producing steel by this method

had been practiced for hundreds of years, but not on this scale.

How big an employer was this steel furnace? Who was working here?

To run this, it would take you and that'll be it.

So it's a one-man job or possibly a two man job

And that was it then?

The whole process from start to finish would be a vast employer

Making chains, making anchors - here they were making billets of steel

They're not taking this and finishing stuff off.

They're producing a product, then giving to somebody else.

It was the bigger plants where they're doing everything

They took it from raw materials to finished product and it was this hive of activity

But of course unfortunately by 1890 this place has gone, finished.

The furnace had gone out, quite literally

The next evolution of the whole place was a road was driven through the forge

to furnish a drift mine, a coal mine

That's all gone. Now we've got a valley

When did English Heritage take guardianship of the Derwentcote Steel Furnace?

And what condition was it in at the time?

It was taken into guardianship in 1985

and it was in pretty poor condition. But it was also the rest of the

landscape that's also a scheduled monument

It's been afforded a level of protection by the state as well

And so what about the work that's required here at Derwentcote in order to

preserve this for future generations to come and enjoy and to learn about our industrial past?

It's not a sort of building that's going to fade away quite quickly.

It's a huge substantial piece of masonry

The main thing you've got to do with this place is keep the water out

Keep it dry and it'll last forever.

Well I hope so because it's a really exciting part of our history and it's great to come

and learn more about it from you today, Mark.

- Thank you so much - My pleasure

From a distance this site may seem barely worthy of note

But as we've learned today, it's a hidden gem

in the local, the national and the international story of steel production

It's also early proof that the north of England would play a

key role in the Industrial Revolution and that England

as a whole would be swept up in a pioneering period of manufacturing and industrialisation

The area around Derwentcote Steel Furnace

is open all year round and the furnace itself is open on special days

To find out more, check the English Heritage website