London - Britain will fail to meet a government target to reduce the number of migrants entering the country to below 100 000 a year, business secretary Vince Cable said.
Prime Minister David Cameron promised in the run-up to the 2010 election to cut net migration to the "tens of thousands" by 2015, down from the 200 000 a year expected under current trends.
Cable, a member of the Liberal Democrat party which traditionally holds a pro-immigration stance, said that the target would most likely not be achieved due to a variety of factors the government cannot influence.
"It involves British people emigrating, you can't control that. It involves free movement within the European Union, in and out. It involves British people coming back from overseas who are not immigrants but are counted in the numbers", Cable told the BBC.
"Setting an arbitrary cap is not helpful. It almost certainly won't achieve the below 100 000 level the Conservatives are setting", he said.
Trailing in the polls ahead of European elections in May and national polls next year, Cameron is striving to stem a right-wing threat from the anti-immigration UK Independence Party.
In December, the government brought forward measures that will force EU migrants to wait three months before they can apply for benefits.