By Agence France-Presse The British government launched a phone app Monday to allow EU nationals to apply to stay after Brexit, hoping to ease concerns among those who have made their lives in Britain. Around 3.5 million Europeans currently living in Britain will need to apply for "settled status" to continue to work and claim benefits after Brexit. The app launch is a test stage before the scheme becomes fully operational on March 30, the day after Britain is due to leave the European Union. It will stay open until late 2020 or 2021. Around 3.5 million Europeans currently living in Britain will need to apply for "settled status" to continue to work and claim benefits after Brexit (AFP Photo/Tolga AKMEN / MANILA BULLETIN) Prime Minister Theresa May has said repeatedly she wants Europeans living here to stay. Officials have vowed to make the process as easy as possible, but there are concerns at how they will cope with what some estimates suggest could be 6,000 applications a day. Talks continue with Apple to allow the app to function on iPhones as it currently only works on Android phones. Last year the Home Office interior ministry came under intense criticism for threatening to deport Britons whose parents, the so-called Windrush generation, migrated from the Caribbean after World War II. They were legally British but some people who could not produce official proof were told to leave Britain or refused the right to return home after visiting relatives abroad. The EU scheme "is an important test for the Home Office. The stakes are high", said Jill Rutter, of the British Future think-tank. "Get it right and the UK sends a strong message that EU citizens are welcome and the government is in control. Get it wrong and the consequences are dire." 'Well on track' The Home Office reported positive results from a trial of the app conducted on 30,000 people during November and December. No applications were refused and 81 percent were processed within a week. But almost ten percent were still unresolved three weeks after the trial ended. "We are well on track to deliver a system that will make it easy and straightforward for EU citizens to obtain status once we have left the EU," Immigration Minister Caroline Nokes said. With the app, users are asked to scan their biometric passport and their face with a phone camera to confirm their identity. They are then directed to a website to input their address and if they want, agree to a real-time check of their tax records to confirm they live in Britain. The third step is to declare any criminal record. A serious conviction could see their application declined. The process costs 65 pounds -- the price of a passport -- but is free for anyone who already has permanent residency in Britain. On March 30 the scheme will open to all applicants, including those without biometric passports. They can post their documents to the Home Office or visit a regional center where someone will help scan them. The Home Office has hired 1,500 caseworkers and 400 call center staff to help guide people through their applications. Officials may even make home visits where necessary. If Britain agrees with divorce terms with the EU, Europeans arriving before the end of 2020 must apply for their new status by June 30, 2021. In the event of no deal, only those who arrived before Brexit day can apply and have until December 31, 2020, to do so.