British Prime Minister David Cameron called the EU referendum to try to heal Conservative party divisions on Europe, but the bitterness of the campaign has sparked fears for its future — and his. Senior Tories on rival sides of the debate have been attacking each other with increasing ferocity, with those backing a so-called Brexit even turning their fire on government policy to make their point. The extent of the internal conflict has raised questions about how long Cameron, who was re-elected last year with a slim parliamentary majority, can survive regardless of the result on June 23. Opinion polls point to a tight race, although the Cameron-backed campaign to “Remain” has a slight lead. “The referendum may well break the Tories,” wrote Philip Stephens, the chief political commentator for the Financial Times. While he said it had been a “delusion” to think the referendum would end decades of divisions on Europe, “the ferocity of the campaign has surprised even the realists”. Philip Johnston of the Daily Telegraph added: “This civil war could destroy one of the most successful and enduring political parties the world has seen.” Their comments echo those of veteran lawmaker Ken Clarke, a pro-European who served