* Tough speech from minister seen as possible successor
* Economic benefits from mass immigration ‘near zero’
* Issue lies at heart of coming EU referendum (Updates after speech, adds reaction)
By William James
MANCHESTER, England, Oct 6 (Reuters) - Mass immigration is damaging British society, Conservative interior minister Theresa May said on Tuesday, promising a tough approach on an issue that will influence Britons’ choice of whether or not to leave the European Union.
“When immigration is too high, when the pace of change is too fast, it’s impossible to build a cohesive society,” May, seen as a possible future leader, told a party conference in the northern city of Manchester.
Mass immigration strained public services like schools and hospitals, depressed wages and pushed people out of work, she said, describing the economic benefits as “close to zero”.
Net migration to Britain reached a high of 330,000 people in the year to March, far above the “tens of thousands” Prime Minister David Cameron promised to reduce it to. More than half comes from EU nationals, who are free to move within the 28-country bloc.
That has fuelled support for rival parties, especially the anti-EU UK Independence Party, and is looming as a major issue in the referendum on Britain’s EU membership that Cameron has promised to call by the end of 2017.
May’s speech went down well with party activists but drew criticism from the Institute of Directors, an employers’ group.
“We are astonished by the irresponsible rhetoric and pandering to anti-immigration sentiment from the Home Secretary,” its director Simon Walker said.
“It is yet another example of the Home Secretary turning away the world’s best and brightest, putting internal party politics ahead of the country.”
As part of a renegotiation of Britain’s EU membership terms with the other 27 countries in the bloc, Cameron is under pressure to deliver reforms to welfare rules to restrict migrants’ access to the British benefits system.
Speaking earlier, Cameron conceded he had missed his immigration target and that there was a need to “reform our welfare system so you don’t get instant access to it when you arrive.”
His bid to tighten such rules received a boost on Tuesday when a senior EU legal adviser recommended that the European Court of Justice dismiss a complaint against Britain brought by the EU executive, which accused London of discriminating against other citizens of the bloc.
Public concern over immigration has been heightened by the arrival into mainland Europe of hundreds of thousands of migrants and refugees fleeing war and poverty in the Middle East, Africa and Asia.
Several thousand have travelled to the French port of Calais, seeking illegal passage to Britain. Their attempts to board lorries and trains have badly disrupted freight and passenger links between the island nation and the continent, stirring nationalist sentiment.
Seeking to grasp control of the issue, which dominated the British media over the summer, May promised to be tough on those who abuse the asylum system and flatly rejected calls for an EU-wide system for processing applications.
“Not in a thousand years,” she said, drawing a round of applause from activists. “We’re not seeking to regain control of our borders with one hand, only to give it away with the other.”
Instead, May said Britain would be tightening up its asylum processing rules to make it easier to send those whose applications have been rejected back to their home countries, even if the authorities there do not want to receive them.
“The message will be clear - if other governments don’t play by the rules, there will be consequences,” she said. (Additional reporting by David Milliken, Editing by Mark Trevelyan)