Don’t think that you have to fly from Liverpool or London if you want to get cheap flights from the UK to Benicassim this year. Manchester has several operators that will get you to Alicante airport which is only around 2 and a half hours drive to the festival site. It also has a train station to get you to Benicassim town. The following airlines fly to Alicante from Manchester airport (cheapest at time of writing is top of the list):
Valencia is the closest major airport to Benicassim, unfortunately there are no longer any direct flights to Valencia from Manchester. Several airlines (Lufthansa etc.) do offer indirect flights to Valencia, however the additional time and cost of these flights makes them an unviable option. To get to Benicassim from Manchester we’d strongly recommend flying in to Alicante and then driving or getting a train to Benicassim.