Amal Clooney has warned that Donald Trump is creating a global hostility towards journalists which is undermining democracy.
The lawyer spoke as a Foreign Office special envoy on media freedom at a conference in London, at the invite of Conservative Party leadership hopeful Jeremy Hunt.
Ms Clooney said there were widespread threats to journalists, and the flames of press distrust were being stoked by the US president.
She said Mr Trump, as leader of the world’s most powerful democracy, was eroding trust in a pillar of democratic society.
Ms Clooney also criticised the ineffectiveness of the global response to the murder of Saudi journalist Jamal Khashoggi in Turkey, and claimed the international system is “broken”.
She also said the UK had a colonial legacy of legislation used to repress press freedom.
The human rights advocate addressed delegates in London at the Global Conference for Media Freedom, and said Mr Trump had worsened hostility towards members of the press.
She said: “If we don’t turn things around, democracy will not survive.
“The global decline in press freedom is being hastened by rhetoric from the leader of the world’s most powerful democracy.
“It will not be reversed without strong leadership from others.”
Ms Clooney added that the international response to forces silencing the media was broken and ineffective.
Speaking at the Printworks in Surrey Quays, the lawyer said Britain’s colonial past had left laws in states around the world which are still being used to silence dissent.
She said: “The international system we have in place is broken. It is so broken that we have record levels of journalists being jailed and killed.
“It is so broken that people like Jamal Khashoggi can be murdered on foreign soil without any co-ordinated investigation, open trial or effective accountability.”
Ms Clooney urged the UK to do more in tackling the issue of press repression around the world, as Mr Hunt announced plans to protect journalists internationally and domestically.
She said: “Many of the problematic laws that are being used to silence journalists around the world also came from British Commonwealth rule.
“The UK’s laws used to criminalise blasphemy and over 40 countries still do, including many former colonial states.
“A British law which criminalised sedition was used in India to prosecute Mahatma Gandhi, and is still on the books in the world’s most populous democracy.”
Ms Clooney has called for the greater use of sanctions against regimes that silence the press, better consular help when journalists are in trouble abroad and a better system of asylum for persecuted foreign journalists.
Amnesty International UK’s director Kate Allen said: “Amal Clooney is right to warn of the dangers presented to journalism by Donald Trump.
“When President Trump describes journalists as ‘enemies of the people’, every journalist around the world is made that bit less safe.
“Journalists already face numerous dangers – from online harassment through to imprisonment or even horrific killings like Jamal Khashoggi’s – and it’s grossly irresponsible of world leaders to publicly denigrate the work of journalists.”