Today The Times revealed that it is the advertiser behind the unbranded London commuter campaign that has been running this week featuring images ranging from Barack Obama to a boy in swimming shorts.

Click here to see a slideshow of all the ads

The Times launched the campaign on Monday, posting the unbranded images at over 70 commuter stations across the capital, with the aim of making people question and think.

A series of half page ads have also run in The Financial Times, The Independent, City AM, Metro, thelondonpaper and The Times.

Within days, the blogsosphere was intrigued:

US political blog Daily Kos reported "Mysterious Obama billboards in London".

Dvorak.org wrote "I saw this billboard yesterday on platform 4 at London Waterloo train station. At first I thought that it was some kind of sneaky political message from the Labour party showing approval for Obama."

Media blogger Rick Lamb started the intrigue, writing: "There's another discussion here which raises the preposterous, but very funny, idea that the Barack Obama image is part of a series of teasers for the new season of Lost."

The Daily Telegraph wrote: "The adverts, which all have bold black backgrounds, started appearing at London Underground stations and on trains earlier this week, and were published in several national newspapers this morning. " (They took down the story once they realised we were behind the ads)

Current.com wrote: "Mysterious adverts featuring images of Barack Obama, David Cameron and the CERN particle collider on London Underground platforms have sparked debate among confused commuters and bloggers."

PositivelyBarack wrote: "Enough about the drama in Washington. Whose ad campaign is this?"

Numerous users of the photo sharing site Flickr posted pictures of the ads, including: Martin , Nefi , Melvin Heng and Drew Benvie.

The purpose of the campaign has been to encourage readers to question and challenge, to think again about our times and to think again about The Times. The same rationale was behind the decision to drop the end line, Join The Debate. The paper wants its readers to make up their own minds about what the paper means to them."

See a slideshow of all the ads