Yesterday's breakthrough follows 12 months of tunnelling, which began at Thames WaterвЂ™s Stoke Newington Reservoir in Hackney.
Daljit Dhanda, Morgan Est Project Manager, said: вЂњThe entire team has done extremely well in delivering this tunnel.
вЂњIt has been a reliable drive and we have had good steady progress in often challenging conditions.
вЂњThe project has been undertaken in a quiet residential area with work continuing 24-hours a day, five days a week.
вЂњThrough constant monitoring of noise levels, effective mitigation measures and a professional disciplined workforce we have ensured the agreed constant levels were not exceeded and have minimised our impact on the local environment.ADVERTISEMENT
вЂњThe breakthrough itself went extremely well and is testament to the consistent dedication and hard work of our team.вЂќ
Morgan EstвЂ™s contract required the construction of a 4.5km tunnel which connects a major water treatment works to the London Ring Main, a 50-mile water tunnel forming a complete ring around the capital.
The finished 2.6m diameter concrete-lined tunnel will link the water treatment plant at Coppermills with the Thames Water Ring Main ensuring greater resilience of LondonвЂ™s potable water supply.
Project completion is scheduled for spring 2010.