Britain has squandered £4.2 million of taxpayers money processing 'absurd' asylum claims by EU citizens, Theresa May will reveal today

Mass immigration is making it impossible to build a cohesive society and is against Britain’s national interest, the Home Secretary will declare today.

Theresa May will warn the Tory conference that huge pressure is being placed on public services and infrastructure by economic migrants.

She will say: ‘There are millions of people in poorer countries who would love to live in Britain, and there is a limit to the amount of immigration any country can and should take.’

Based on the current influx, Mrs May says the UK needs to build 210,000 homes every year and find 900,000 extra school places by 2024.

She will also claim there are ‘thousands of people who have been forced out of the labour market, still unable to find a job’.

Her comments – the strongest by a senior minister in recent times – reinforce the need to get a grip on immigration at a time when some Cabinet ministers are seeking to water down the Tory pledge to cut net migration to tens of thousands.

Mrs May will also reveal that Britain has spent more than £4million processing asylum claims by EU citizens at no risk of persecution. Many of the claimants are from Spain, where millions of Britons take holidays, and Poland.

The claims have no chance of success but, under existing rules, applicants are entitled to a full interview.

The Home Secretary will tell the Tory conference in Manchester she is scrapping the ‘absurd’ rules, so claims by EU nationals will be inadmissible unless there are exceptional circumstances – for instance if they are victims of people trafficking.

Mrs May, who speaks before leadership rival Boris Johnson, will say: ‘People on both extremes of the debate – from the anti-immigration far Right to the open-borders liberal Left – conflate refugees in desperate need of help with economic migrants who simply want to live in a more prosperous society.

Their desire for a better life is perfectly understandable, but their circumstances are not nearly the same as those of the people fleeing their homelands in fear of their lives.

‘While we must fulfil our moral duty to help people in desperate need, we must also have an immigration system that allows us to control who comes to our country.

'When immigration is too high, when the pace of change is too fast, it’s impossible to build a cohesive society.

‘It’s difficult for schools and hospitals and core infrastructure like housing and transport to cope. And we know that for people in low-paid jobs, wages are forced down even further while some people are forced out of work altogether.

Hundreds of migrants who arrived by train on the Hungarian-Austrian border walk the four kilometres into Austria earlier this month

‘Now I know there are some people who say yes, there are costs of immigration, but the answer is to manage the consequences, not reduce the numbers. But not all of the consequences can be managed, and doing so for many of them comes at a high price.

'But even if we could manage all the consequences of mass immigration, Britain does not need net migration in the hundreds of thousands every year.

'Of course, immigrants fill skills shortages and it’s right that we should try to attract the best talent in the world, but not every person coming to Britain right now is a skilled electrician, engineer or doctor.

‘The evidence... shows that while there are benefits of selective and controlled immigration, at best the net economic and fiscal effect of high immigration is close to zero. So there is no case, in the national interest, for immigration of the scale we have experienced over the last decade.’

In a hard-hitting speech at Tory conference, Mrs May will warn mass immigration is making it 'impossible' to build a cohesive society and is against Britain's 'national interest'

In an exclusive interview with the Mail, ahead of the speech, the Home Secretary slapped down Cabinet colleagues who are trying to dilute the Government’s commitment to cut net migration to the tens of thousands.

Last month, it emerged that Foreign Secretary Philip Hammond, Chancellor George Osborne and Business Secretary Sajid Javid want non-EU students to be omitted from the target.

Campaigners for stricter border controls are concerned that ministers might seek to drop the target altogether, given it has been repeatedly missed and net migration – the difference between the number entering the country and leaving each year – is at an all-time record of 330,000.