Foreign doctors wanting to treat NHS patients in England will have to prove they have the necessary English skills, the government has confirmed.
Concerns were raised after a German doctor, Dr Daniel Ubani, gave a patient a fatal overdose on his first and only shift in the UK.
He had earlier been rejected for work because of poor English skills.
From April there will be a legal duty to ensure a doctor's English is up to scratch before they are employed.
Foreign doctors will have to prove they can speak a "necessary level of English" before they are allowed to treat patients in hospitals or in GP surgeries, the Department of Health said.
Dr Ubani had been refused work by Leeds Primary Care Trust, but was later employed in Cambridgeshire.
From April, there will be a national list of GPs to prevent doctors being rejected in one part of the country and then cropping up somewhere else. GPs will have to prove their language skills before being put on the list.
Health minister Dr Dan Poulter said the measures were about protecting patients, who "should be able to understand and be understood by their doctor if we are to give them the best care they deserve".
"These new checks will ensure that all doctors who want to work in the NHS can speak proficient English and to prevent those who can't from treating patients," he said.
New powers for the body which regulates doctors in the UK - the General Medical Council - are also being discussed. A change of law could give it powers to test the communication skills of doctors from within the EU as it already can for non-EU doctors.
Niall Dickson, chief executive of the GMC, said tighter rules would "strengthen patient safety".
He added: "Our position is clear - patients must be confident that the doctor who treats them has the right communications skills to do the job.
"If doctors cannot speak English to a safe standard then the GMC must be able to protect patients by preventing them from practising in the UK.
"At present we can do that for doctors who have qualified outside Europe but we cannot do it for doctors within the European Union.
"We have been working hard for some time to close this loophole in UK legislation which has caused so much concern to patients and their families and we are delighted that the government has decided to act."
Katherine Murphy, chief executive of the Patients Association, said: "New language checks for doctors are welcome, and long overdue.
"Lessons from the past have served to highlight the tragic consequences of poor language skills."
Dean Royles, director of the NHS Employers organisation, said foreign doctors had made an "invaluable contribution" but safety needed to be the "top priority".