London is to continue hosting the ATP World Tour Finals until at least 2018, it has been confirmed.
The news has long been expected and ATP president Chris Kermode made the announcement at the draw for the 2015 tournament on Thursday.
"We're very pleased to announce that we're going to be staying in London through to 2018," he said. "We hope that for these years the event can grow from strength to strength."
London mayor Boris Johnson added: "ATP, congratulations to you - You have done exactly the right thing, you have chosen London once again.
"It is not only the home of all the great sporting competitions you could think of - from the Olympics to the Rugby World Cup, NFL, European Swimming Championships, diving - it is also, as I never tire of telling you, the place where virtually every single sport of any importance or interest was either invented or codified.
After regaling the gathered crowd with tales of how the likes of athletics, rugby union and hockey had their beginnings in the English capital, Johnson asked: "And where was tennis invented? Unfortunately it was Paris, rather irritatingly for our purposes tonight.
"But never mind, because we have got the ball back over the net by having the greatest [indoor] tennis tournament in the world here in London and we are delighted."
London has hosted the season-closing event at the O2 Arena since it was first staged under its current guise in 2009, with Novak Djokovic having won the last three.