British PM Cameron's party says likely to fail to cut immigration LONDON (Reuters) - British Prime Minister David Cameron's Conservatives said on Sunday they were unlikely to keep a promise to reduce net migration to "tens of thousands," possibly damaging their reelection chances next year. Immigration has shot to the top of voter concerns before a 2015 national election after the UK Independence Party (UKIP), which wants to limit inflows and leave the EU, won European elections in Britain in May and later secured two seats in the British parliament. Cameron's party has promised to cut net migration to the tens of thousands by next year's election in May. Instead, it rose to 243,000 in the year to March 2014 and new data due this week is expected to show the numbers getting higher, not lower. "It is of course unlikely that we're going to reach the tens of thousands by the end of the parliament," Home Secretary (interior minister) Theresa May said on Sunday. Why is that? It's because we've seen increasing numbers of people coming from across Europe, partly because our economy is doing better," she told BBC TV's Andrew Marr Show. Though an apparent statement of the obvious, the comments by May, tipped as a possible contender to replace Cameron, are significant because her party has until now been unwilling to concede defeat on such a major election issue. Fearing UKIP will split the right-wing vote next year and make it harder for him to get re-elected, Cameron, who heads a coalition with the centrist Liberal Democrats, has hardened his rhetoric on immigration and taken modest measures to curb it. The issue is linked to Britain's EU future. Cameron has promised to renegotiate the country's EU ties if re-elected, before holding a referendum on membership in 2017. He has said he would use such a renegotiation to try to win concessions to limit EU migrant numbers, something that is anathema to some EU leaders who say the bloc's rules on freedom of movement of workers are sacrosanct. Cameron is expected to deliver a speech on the issue this week in which he is likely to set out his ideas for making Britain a less attractive country for EU migrants. Local media suggest he may pledge to ban EU migrants from claiming welfare benefits for low-wage earners, for example tax credits or subsidized housing, until they have worked in Britain for a certain period of time.