LONDON, July 2 (Reuters) - Britain said on Friday it had received 6 million applications to its settlement scheme for European Union nationals before a June 30 deadline passed, including a surge of more than 400,000 in the last month. After completing its exit from the EU last year, Britain has started bringing in a new immigration system. EU citizens who can prove they were living in Britain before Dec. 31 last year will retain the right to work, study and access benefits. The data showed 6.02 million applications had been received by June 30, of which 5.45 million had been concluded. "I am delighted that we have secured the rights of so many EU citizens - our friends, neighbours and family members," interior minister Priti Patel said. Of those concluded applications, 4% have either been refused, withdrawn or invalid. The rest were either accepted as settled or "pre-settled", meaning residency rights were retained. A high-profile publicity campaign to remind people to apply reflected concerns that some eligible residents might have been unaware of the scheme, or lacked the ability to submit an application. The number of those who failed to apply in time is uncertain, but campaign groups and lawyers have warned that tens of thousands of EU nationals might miss the deadline because they did not realise they needed to apply. Landlords and employers will now be able to ask for proof from EU nationals of their immigration status. While the Home Office said EU citizens who had not applied would be granted leniency in certain circumstances, those who missed the deadline might be issued with a formal 28-day notice and risk temporarily losing right to services such as free non-urgent healthcare Three years ago the government apologised for the Home Office"s treatment of thousands of Caribbean migrants, who were denied basic rights, including some who were wrongly deported, despite having arrived legally in Britain decades earlier.