Mark Webber grabbed pole position on Saturday for Sunday's British Grand Prix as Red Bull swept the front row again in changeable conditions during an unpredictable qualifying session.The 34-year-old Australian, who won last year's race, demonstrated his liking for the Silverstone circuit with a fastest lap of one minute and 30.399 seconds as his team locked out the front row again.It was Webber's second pole this season and the seventh of his career.Spaniard Fernando Alonso was third fastest for Ferrari ahead of his team-mate Brazilian Felipe Massa as rivals McLaren struggled to mount a serious challenge.Briton Jenson Button, in the leading McLaren, was fifth and his team-mate and compatriot Lewis Hamilton was only able to qualify in 10th place.Another Briton, Scot Paul Di Resta, took sixth place on the grid for the Force India team ahead of Venezuelan Pastor Maldonado in a Williams with Japanese Kamui Kobayashi eighth for Sauber and German Nico Rosberg ninth for Mercedes. Related article: Row over technical rules U-turnOn a cool, damp and drizzly afternoon at the revamped old circuit in central England, the entire field was swiftly out in pursuit of times early in Q1 - all going for banker times in case of subsequent heavy rain making the track more treacherous and slower.Many of the teams had been involved in frantic activity before the session following a morning of technical meetings, rows and u-turns on the rules.Massa was soon on the radio warning of "rain at Copse" before his team-mate Alonso lost control at Brooklands and slid off into the gravel at Luffield.He recovered, rejoined and was soon back among the pace-setters.Vettel was soon setting the pace for Red Bull before he was out-paced by team-mate Webber and then Maldonado of Williams and Massa, Webber's improved best lap remaining the fastest.Heavy rain then curtailed the first mini-session leaving Webber on top and seven men eliminated, including debutant Australian Daniel Ricciardo."It was not easy in those conditions," said Ricciardo."But it is a great feeling to race here in front of these crowds. I have to take it easy as it is my first time. For me, Silverstone is like a second home - I am just going to learn as I go."The rainstorm had cleared before Q2 started with Massa topping the session ahead of Webber and Alonso while seven more men failed to make the top ten cut including Michael Schumacher.Also out after Q2 was German Adrian Sutil of Force India, which meant Di Resta had out-qualified his team-mate seven times in nine race weekends this year.