Theresa May vowed to deliver an immigration system that 'serves the national interest' today as she put regaining control of Britain's borders at the centre of her plan for Brexit.

Ending EU freedom of movement rules would be a top priority in the upcoming negotiations with Brussels, she said.

And although she insisted UK firms will continue to be able to fill skills shortages by recruiting foreigner workers, the Prime Minister acknowledged that the 'sheer volume' of migration over the last decade had put a huge strain on public services.

Theresa May vowed to deliver an immigration system that 'serves the national interest' as she put regaining Britain's borders at the centre of her plan for Brexit

Mrs May's announced the red line on immigration in her keynote speech today in which she set out her bold blueprint for cutting ties with Brussels.

She announced 12 objectives for the Brexit negotiations, which Downing Street said would almost certainly last for the maximum two-years permitted in EU rules.

And the final deal the PM strikes with EU leaders will be put to a vote in Parliament, which will be legally binding on the Government.

Mrs May insisted Britain will still attract the 'brightest and the best' to work and study in Britain and told Brexit hardliners that the UK's openness to international talent must remain 'one of this country's most distinctive assets'.

But she added: 'That process must be managed properly so that our immigration system serves the national interest.

'So we will get control of the number of people coming to Britain from the EU.

'Because while controlled immigration can bring great benefits – filling skills shortages, delivering public services, making British businesses the world-beaters they often are – when the numbers get too high, public support for the system falters.'

Mrs May warned that the EU could be 'crushed into tiny pieces' if it did not recognise the demand for more sovereignty

Explaining how she had seen first-hand the pressures open-door immigration had put on public services, Mrs May said: 'In the last decade or so, we have seen record levels of net migration in Britain, and that sheer volume has put pressure on public services, like schools, stretched our infrastructure, especially housing, and put a downward pressure on wages for working class people.

'As Home Secretary for six years, I know that you cannot control immigration overall when there is free movement to Britain from Europe.

Mrs May also sought to reassure EU nationals already living in the UK and British expats living on the continent

She added: 'Britain is an open and tolerant country. We will always want immigration, especially high-skilled immigration, we will always want immigration from Europe, and we will always welcome individual migrants as friends.

'But the message from the public before and during the referendum campaign was clear: Brexit must mean control of the number of people who come to Britain from Europe. And that is what we will deliver.'

Mrs May also sought to reassure EU nationals already living in the UK and British expats living on the continent.

She said securing their future right to stay is among the 12 objectives in her Brexit blueprint.

The PM said: 'We want to guarantee the rights of EU citizens who are already living in Britain, and the rights of British nationals in other member states, as early as we can.

'I have told other EU leaders that we could give people the certainty they want straight away, and reach such a deal now.

'Many of them favour such an agreement - one or two others do not - but I want everyone to know that it remains an important priority for Britain – and for many other member states – to resolve this challenge as soon as possible. Because it is the right and fair thing to do.'

Other top priorities laid out by Mrs May today include pledges to end the jurisdiction of European judges over British law, pulling the UK out of Europe's single market but promising business 'certainty wherever we can' during the tumultuous negotiations.