Turkish citizens voted on Sunday in a referendum which would give sweeping new powers to President Recep Tayyip Erdogan.

If the electorate votes “yes”, the role of prime minister would be abolished and executive power would be transferred to Mr Erdogan. Under the proposed changes, the President could in theory hold office until 2029.

He would also be able to appoint judges, pass decrees and have greater influence over the civil service.

The “Yes” campaign say the proposed changes would streamline Turkey’s political system, and point out the both the US and France have an executive presidency.

However, opponents fear the concentration of the power in the office of the Presidency will hasten the country’s drift towards authoritarianism.

Polls published earlier this week predicted a narrow majority for “yes” - between 51 and 52 per cent.

However, the referendum is clearly on a knife edge - with one poll stating that 8 per cent of Turks were still undecided.

In the run-up to the election, many Turkish commentators and activists have said the President’s crackdown on journalists has stifled debate around the referendum.

In the aftermath of the attempted coup against President Erdogan last year, at least 130 media organisations have been shut down.

There are currently around a hundred journalists in prison in Turkey, according to the international press freedom watchdog Reporters Without Borders (RSF).

Erol Önderoglu, RSF's representative in Turkey, told The Independent the government had been "intimidating Turkish civil society" in the lead-up to the referendum.

"Many journalists are behind bars, so the referendum will have been achieved, unfortunately, without any criticism of the government from a major TV station, for example.

"It goes without saying that state-owned TV channels and all the pro-government stations have, in a systematic manner, covered only the government’s perspective.

Turkey riots latest: Erdogan blames 'extremists' for nationwide riots as protester, 22, is killed near Syrian border Show all 13 1 /13 Turkey riots latest: Erdogan blames 'extremists' for nationwide riots as protester, 22, is killed near Syrian border Turkey riots latest: Erdogan blames 'extremists' for nationwide riots as protester, 22, is killed near Syrian border Turkey-AFP.jpg AFP/Getty Images Turkey riots latest: Erdogan blames 'extremists' for nationwide riots as protester, 22, is killed near Syrian border turkey-rt.jpg Protesters in Ankara shout anti-government slogans Reuters Turkey riots latest: Erdogan blames 'extremists' for nationwide riots as protester, 22, is killed near Syrian border 24-turkey3-rt.jpg A group in the city clash with riot police Reuters Turkey riots latest: Erdogan blames 'extremists' for nationwide riots as protester, 22, is killed near Syrian border turkey-1.jpg A protester walks past a burning car at Taksim Square in central Istanbul Reuters Turkey riots latest: Erdogan blames 'extremists' for nationwide riots as protester, 22, is killed near Syrian border turkey-9.jpg Protestors clash with riot police near Turkish prime minister Recep Tayyip Erdogan office, between Taksim and Besiktas in Istanbul Getty Images Turkey riots latest: Erdogan blames 'extremists' for nationwide riots as protester, 22, is killed near Syrian border turkey-2.jpg Anti-government protesters clash with riot police during a demonstration in Ankara Reuters Turkey riots latest: Erdogan blames 'extremists' for nationwide riots as protester, 22, is killed near Syrian border turkey-7.jpg An anti-government protester holds a Turkish national flag with a portrait of Mustafa Kemal Ataturk, founder of modern Turkey, on it during a demonstration in Ankara Reuters Turkey riots latest: Erdogan blames 'extremists' for nationwide riots as protester, 22, is killed near Syrian border turkey-4.jpg Protestors clash with riot police near Turkish prime minister Recep Tayyip Erdogan office, between Taksim and Besiktas in Istanbul Getty Images Turkey riots latest: Erdogan blames 'extremists' for nationwide riots as protester, 22, is killed near Syrian border turkey-6.jpg Protestors clash with Turkish riot police on a excavator as they try to reach to the office of Turkey's Prime Minister Tayyip Erdogan during an anti-government rally at Besiktas district in Istanbul, Turkey EPA Turkey riots latest: Erdogan blames 'extremists' for nationwide riots as protester, 22, is killed near Syrian border turkey-5.jpg Protestors clash with Turkish riot police as they try to reach to the office of Turkey's Prime Minister Tayyip Erdogan during an anti-government rally at Besiktas district in Istanbul, Turkey EPA Turkey riots latest: Erdogan blames 'extremists' for nationwide riots as protester, 22, is killed near Syrian border AN22156086An-anti-governmen.jpg An anti-government protester waves Turkey's national flag bearing a portrait of Mustafa Kemal Ataturk, founder of modern Turkey, during a demonstration GETTY IMAGES Turkey riots latest: Erdogan blames 'extremists' for nationwide riots as protester, 22, is killed near Syrian border Turkey-REUTERS.jpg Protesters attempt to tip a police car during anti-government protests in Taksim Square Reuters Turkey riots latest: Erdogan blames 'extremists' for nationwide riots as protester, 22, is killed near Syrian border turkey-8.jpg A riot policeman reacts to a fire made by anti-government protesters during a demonstration in Izmir, western Turkey Reuters

"In a referendum process... people should have access to different points of view and be informed properly. This is the opposite of what has happened in Turkey."

The government is also fighting a military campaign against the Kurdistan Workers' Party (PKK) in the south-east and is restricting press coverage of the campaign.

Thousands of Kurdish people displaced by conflict in Turkey may not be able to vote because of their lack of an address, according to Turkey’s Independent Election Monitoring Network.

Mr Erdogan became Turkish president in 2014, after more than a decade as prime minister. He has transformed the role, which was largely ceremonial before he took office.