Stratford schoolboy Ryan Waters watched in awe as the giant drilling machine he named “Busy Lizzie” was lowered into the ground in Beckton to dig the historic River Lee Tunnel.

Ryan Waters, 10, said: “It is really exciting to see the name on the machine, it’s so massive!

“I signed it so it’s got my name on it now and that’s pretty cool.”

Ryan, a pupil at Maryland School, won a borough-wide competition to name the machine which is 8 metres in diameter - wider than three double decker buses side-by-side - and 120 metres long.

“Busy Lizzie” is the first piece of a drill which will dig the �635 million River Lee Tunnel project to prevent 16 million tonnes of sewage entering the River Lee each year, due to out-of-date Victorian sewers being too small to cope with heavy rainfall.

Lucky classmates Safa Mahmood, 10, and Denzel Day, 11, went with Ryan to watch the 800 tonne “Busy Lizzie” being lowered into position at Beckton Sewage Works, a four-hour operation using one of the biggest cranes in Europe, transported in 60 lorry loads.

Safa said: “I have never seen anything that big before. When they came and told us about the naming competition, I couldn’t even imagine the size of it. The whole class is really jealous that we got to come.”

Denzel added: “You only ever see stuff like this on television.”

Martin Baggs, Thames Water’s chief executive, was there to greet Ryan on the day.

He said: “This is a major milestone on our way to creating a cleaner, healthier River Thames and River Lee, by dealing with the unacceptable problem of sewer discharges into the river during heavy rainfall.

“The Lee Tunnel will tackle discharges from the largest overflow at Abbey Mills in Stratford, which accounts for 40 per cent of the total discharge. That’s why we’re dealing with this, the worst one, first.”

Tunnelling is due to start next month and it will progress at a rate of 17 metres a day, expecting to finish in late 2013 Abbey Mills Pumping Station in Stratford.