And they're off... what has the first day of the election campaign told us? 

The political parties have been setting out their election campaigns, with voters going to the polls exactly six weeks from today.    On the Sky News Daily Niall Paterson speaks to deputy political editor Sam Coates who is following the prime minister on his campaign trail around the UK, visiting four nations in two days. He also chats with chief political correspondent Jon Craig about the launch of Labour's campaign in Kent.    Plus, Sky's online campaign correspondent Tom Cheshire tells Niall why the parties are spending big money online and whether it could affect the election outcome. Producers: Soila Apparicio, Emma Rae Woodhouse Promotions Producer: Jada-Kai Meosa John Editor: Wendy Parker