Guardian Daily: Blair's back - but can he give Brown the bounce at the polls?

Tony Blair has returned to the political fray with a speech in his former constituency of Sedgefield in which he took apart the Conservatives' ptich to voters and praised Gordon Brown's leadership. Guardian columnist Michael White says - love him or hate him - the former prime minister's poltiical skills are still peerless. An alarmingly high number of cancers are being misdiagnosed due to mistakes by doctors and nurses - and NHS patients are dying as a result, according to a report seen by health correspondent Denis Campbell . Russian security officials have warned there may be further terrorist attacks following Monday's suicide bombings on the Moscow metro, reports Luke Harding . After 20 years and billions of pounds of investment, the most complex machine ever built - Cern's Large Hadron Collider - has begun working. As our science correspondent Ian Sample explains, it aims to reproduce what happened just after the big bang. As Latino singer Ricky Martin announces on his website that he's gay, Guardian music writer Rosie Swash considers how easy it is for modern pop stars to be open about their sexual orientation.