A 500 m stretch of the 36 inch-wide pipe, running just outside the entrance to the Marylebone Cricket Club (MCC), is being relined to reduce the risk of any disruptive leaks or bursts.
The £1.5 million project, due for completion in June, will use a 'no-dig' method of relining to perform the work.
The work is scheduled to finish before the historic ground doubles as a stage for the London 2012 Olympics Games archery competition.
This work is part of Thames Water’s ongoing commitment to reduce leakage in the capital. Thames Water has cut leakage by a third since its peak in 2004 by replacing more than 1,400 miles of old mains. Last year the company hit its leakage-reduction target for the fifth year in a row, and is aiming to make it six from six this year.Article continues below…
In December, Thames Water finished working in Kilburn High Road, more than a month ahead of schedule, on a £2 million project to reline 1 km of a 24-inch cast-iron pipe which had burst five times in three years.