The tunnel extending the Dockland Light Railway (DLR) under the River Thames to Woolwich Arsenal was completed on time on 23 July 2007 as the 540-tonne boring machine broke through the earth south of the Thames.

The £180 million, 2.5km extension will link Woolwich south of the river with DLR station, King George V, in North Woolwich, one stop away from London City Airport.

The extension will be important in improving the whole transport network in the run up to the 2012 Games.

The extension will provide a direct link from Woolwich to central London (Bank station) in under half an hour, London City Airport in five minutes, Canary Wharf in 19 minutes and Stratford in 20 minutes. In peak periods, trains could run every four minutes.

There will also be an interchange with mainline services on the North Kent line.

Ken Livingstone, Mayor of London, said: "This is another example of Transport for London (TfL) delivering major transport projects on time and within budget. The Docklands Light Railway is a fantastic success story for London with steadily rising passenger numbers and more and more areas being linked to improve access to new jobs and housing, helping to transform areas of East London. The extension to Woolwich will boost the local economy and completes another piece of the transport improvements the 2012 Games are already bringing to London."

Nicky Gavron, Deputy Mayor of London, said: "This a major milestone in the Docklands Light Railway Woolwich Arsenal extension project, delivered on time and on budget. Once completed in 2009, this vital new transport link joins up communities across the Thames to support the regeneration of Woolwich and the southern Royal Docks, whilst forming a vital part of the 2012 Games transport legacy."

Peter Hendy, London’s TfL Commissioner said: "This is a crucially important day for the DLR, and local residents around here, who will benefit massively from this efficient, reliable, cross-river connection.The DLR carried 60 million people last year and this extension is another example of how this gem of a railway is growing."

Hugh Sumner, Director of Olympic Transport of the Olympic Delivery Authority, said: "The completion of this impressive tunnelling project marks a significant milestone on the road to the London 2012 Olympic and Paralympic Games. The Woolwich Arsenal extension will provide a fast and efficient link between the Olympic Park and the equestrian and shooting events. And it will leave an important legacy for the communities it will serve in the years after 2012."