Under the pub
A step down through an entrance at the side of the pub brings you into the cellar – complete with a waterwheel. On the back wall alcoves can be seen in the brick courses where the gears of huge bellows would have stood. On the opposite wall some evidence of a blowing arch can be seen. This is where the air from the bellows would have been forced into the furnace. The actual furnace itself would have stood outside the current structure of the pub, in what is now the car park.

To start off Day One, John Gater and Chris Gaffney of the geophysics team are busy running up and down the pub car park with their ground-penetrating radar equipment. It's hoped the geophysics will detect evidence of some kind of factory yard or associated buildings.

Trench One is opened close to the wall of the pub. This is where geophysics picks up some particularly strong signals that could indicate a structure – or possibly the base of a furnace. Trench Two is opened just a few metres away. 'We were going to investigate John's blob,' says series producer Tim Taylor. 'It was something that geophysics picked up that looked a bit funny. If we were lucky we would locate an industrial waste slag pile that would confirm if the furnace was fired by charcoal or coke.' Furnaces were originally fired by charcoal, but the development of coke burning by Abraham Darby in 1709 started the Industrial Revolution in iron manufacture.

'Something used to be there'
By mid afternoon Trench Three is opened, also in the car park. 'We were trying to find some evidence for a building,' says Time Team digger, Jenni Butterworth. 'A building appeared on an early map, so we knew that something used to be there.' It's hoped that excavation will reveal if the building was anything to do with any manufacturing that happened on the site.

Trench Four is opened inside the cellar itself to determine what exactly is going on. Industrial archaeology specialist Rob Kinchen-Smith was especially happy with how the work was going in this trench: 'I thought there was definitely good evidence for a furnace there. In the wall that was uncovered you could see where the sandstone sides of the furnace would have been.'

Later on the first day, Trench One is extended; Trenches Two and Three remain at their original size of two metres by three metres. All of them continue to get deeper. But by the end of Day One finds have been few and far between (apart from the furnace!). Right at the end of the day some dark-coloured marks in the soil of Trench One (on the outside wall of the cellar) look as though they could indicate where a substantial wall once stood. Trench Two (site of a geophysics anomaly) is still full of make-up material used for levelling the car park. Trench Three (site of a building shown on an early map) is only a few centimetres deep, and Trench Four (in the cellar) has revealed some interesting furnace-like features.

Casper the dog
To start Day Two a mechanical digger moves into position and starts extending Trench One to encompass Trench Two and make one large trench. The vehicle's driver, Grant, soon breaks up even more of the pub car park and the trench grows at a rapid pace. It's all done under the watchful eyes of Casper the driver's trusty dog.

Trench Three reveals some brick and stone courses just 30 centimetres beneath the surface. 'That was the building we were looking for,' says Jenni Butterworth. 'It dated to about the mid 1800s, which fitted well with the one on the early map.' Meanwhile a large tanker is brought onto site to suck out all of the stagnant water lying in the bottom of the wheel trough. Work soon starts in this area to try to determine any phases of construction and use of the wheel.

'Whoa, whoa, whoa!'
Around 4pm on Day Two a discovery is made. 'Whoa, whoa, whoa!' shouts Phil from the side of Trench One. Jumping in, trowel in hand, he digs away some of the edge next to where the digger bucket was scraping. 'Look at that!' he enthuses. 'We've got a lovely bit of worked stone curving around the left-hand side. Looks like we've found a bit of the casting arch.' An arched stone stands proud in the side of Trench One confirming the location of the casting arch, which sits on the furnace base.

'What we were hoping to do next was find the casting floor,' says Tim Taylor. 'This was the lower working surface of the foundry. This is where the liquid metal would have run out into moulds to cast pig iron.' Pig iron is so called because the ingot blanks of pure iron that were produced were set in moulds that ran off from a central channel. These were said to resemble a sow and her feeding piglets.

The story comes together
Day Three sees the Team trying to find the level of the casting floor, and some terraces in the adjacent fields also need to be fully investigated as they could point towards the site of some domestic settlement associated with the furnace.

Landscape investigation highlights how water was channelled into the furnace and Stewart discovers a small stone bridge near the site. Documentary evidence states that the bridge was built in the 17th century to allow the product of Leighton furnace to be transported to a wharf on the river Severn. Slowly the story comes together. The search for domestic settlement proves fruitless, but finally in Trench One the deep sand casting floor of the furnace is reached.

Special analysis on the slag deposits excavated confirms that the site only used charcoal for firing. The end of the Leighton furnace as a working site seems to have arrived with the use of coke in iron production. Perhaps this was one of the last charcoal-burning furnaces in the area, eventually overtaken and made redundant by the new coke-burning technology inspiring the Industrial Revolution just a few miles down the road in Ironbridge.