Offer now expired: Get behind the headlines with some of the Guardian's most experienced journalists

How does a journalist happen upon a story that no one else knows about? How does he or she develop it? Can they be sure their source is telling the truth? How do they verify the facts? You can get answers to all these questions at our Extra event offering members an insight into the world of investigative journalism. The venue is the offices of the Guardian and Observer in Kings Place, York Way and the date is 28 October. The event will start at 6.30pm. The speakers will be David Leigh , Investigations Editor at the Guardian, and Nick Davies , a journalist who's worked for the Guardian for many years. They'll be joined by Paul Lewis, who broke the Ian Tomlinson story and is now Special Projects Editor for the Guardian. David Leigh has been an investigative journalist since the 1970s. His 1995 TV documentary for World in Action, "Jonathan of Arabia", led to the jailing for perjury of former Conservative defence minister Jonathan Aitken. With his colleague Rob Evans, David won the Paul Foot Award in 2007 for the BAE bribery exposures. David has worked for The Scotsman, The Times, The Guardian and The Observer. He was a Laurence Stern fellow at the Washington Post in 1980 and in 2006 became the UK's first professor of reporting at City University London. Nick Davies is an investigative journalist, writer and documentary maker. He has written extensively for The Guardian and The Observer, and was named Journalist of the Year, Reporter of the Year and Feature Writer of the Year at the British Press Awards . He was the winner of the first Martha Gellhorn Prize for Journalism in 1999. Nick has made documentaries for ITV's World in Action programme and has also written several books on politics and journalism, including Flat Earth News , which attracted considerable controversy as an exposé of journalistic malpractice in the UK and across the globe. Paul Lewis is Special Projects Editor for the Guardian. He was named Reporter of the Year at the British Press Awards 2010 and won the 2009 Bevins Prize for outstanding investigative journalism. He previously worked at the Washington Post as the Stern Fellow. Tickets to the event cost £10. BOOK TICKETS FOR THIS EVENT Offer now expired HELP WITH OFFERS AND EVENTS •You need to be a member of Extra in order to see the redemption pages. You can sign up here •You also need to be signed in to theguardian.com at the top of the screen to take up any offer or book tickets for an event.