In February, five candidates – Pidgeon, Whittle, Khan, Berry and Goldsmith – appeared in a debate on issues surrounding technology and science at the Queen Elizabeth Olympic Park. Key topics to emerge included the conflict between traditional London Black Cabs and Uber, and the role of the EU in shaping the British technological industry. A few days later, a referendum on the UK's membership of the EU was announced for 23 June, the campaigning for which intersected with the mayoral election. Alongside Whittle, whose UKIP party was founded with the aim of securing the UK's departure from the EU, both Goldsmith and outgoing mayor Boris Johnson announced their intention to campaign to leave the EU, in defiance of their party leader, Prime Minister David Cameron. By contrast, Khan, Pidgeon and Berry all declared their support for remaining in the EU. George Eaton of the "New Statesman" noted that research from the "British Election Survey" had found that voters in London (a majority-minority city), typically showed more support for the EU than voters in the UK as a whole.