Britain’s last detainee in Guantanamo Bay is finally coming home after a Daily Mail campaign for justice.

After a grotesque ordeal lasting 14 years, Shaker Aamer has been told he will be released from the notorious military prison within a month.

The US has bowed to mounting pressure to free the 48-year-old terror suspect, who has languished behind bars without charge or trial since February 2002.

The surprise announcement yesterday represents a major victory for the Mail’s tireless campaign for the married father-of-four’s release.

Mr Aamer’s jubilant family last night thanked the newspaper for its ‘huge contribution’ in securing his freedom. His father-in-law, Saeed Siddique, 72, said the paper’s campaign had been an important factor in persuading the US authorities to release him.

Shaker Aamer, the last British resident held at Guantanamo Bay, will be flown back to Britain after spending 14 years behind bars in the controversial detention centre

Speaking from a joyful family gathering at his daughter Zineera’s home in Battersea, South London, he said: ‘We appreciate so much all the support we have received from the Daily Mail. Your many articles have made a huge contribution. They have been very, very helpful by bringing attention to the injustice he has suffered.’

A US State Department source confirmed the Mail’s campaign had been a significant factor in the decision to release Mr Aamer.

‘It mattered. It absolutely made a difference,’ the source said.

Mr Aamer, who claims he has been abused in the presence of British security agents, is now in line for a compensation payment of up to £1 million. In 2010, similar sums were given to British Guantanamo detainees to settle damages claims and head off what the Government believed would be costly and embarrassing court cases that would drag UK intelligence services into the dock.

Last night Mr Aamer’s daughter Johina, 17, tweeted: ‘Thank you everyone for all the support. The news hasn’t hit yet. We can’t believe we might finally see our dad.’

President Barack Obama informed David Cameron of the decision to release Mr Aamer during a phone call on Thursday night.

US Defence Secretary Ashton Carter signed off the transfer following a ‘thorough review of his case and taking into consideration the robust security assurances that will be provided by the British Government’.

Mr Aamer’s release is expected to take place once the 30-day notice period set by the US authorities has expired.

Britain is expected to send a plane to the jail in Cuba to pick him up. He will not be arrested but is expected to be ‘debriefed’ by the security services.

He will undergo psychological and medical tests to assess his condition following years in captivity, during which he claims to have been tortured. He is likely to be placed under intense surveillance by the security services to safeguard against any risk of him turning to terrorism.

The decision to release Mr Aamer follows high-level lobbying by the Government. In January, Mr Cameron won plaudits when President Obama vowed to ‘prioritise’ the terror suspect’s release following top-level talks at the White House.

SHAKER AAMER: THE SAUDI-BORN LONDONER WHO TOOK HIS WIFE AND FOUR CHILDREN TO AFGHANISTAN BEFORE BEING SENT TO GUANTANAMO Shaker Aamer has been imprisoned since Valentine's Day 2002, without ever being charged or standing trial, and has a wife and children in South London, and has never met his 13-year-old son Shaker Aamer was born in Saudi Arabia, but his wife and four children are British citizens. His youngest son Faris was born on the same day Mr Aamer arrived at Guantanamo - on Valentine's Day 2002 - and has never met his father. Mr Aamer moved with his pregnant wife and young family to Afghanistan in 2001, where he says he was working for a charity. But with coalition forces entering Afghanistan to drive out al Qaida after 9/11, legal charity Reprieve claims he was abducted and sold for a bounty to US forces. His family and campaigners have made repeated calls for him to be released and reunited with his wife and children at their south London home. In February, Mr Aamer's son Michael, 15, said a part of his heart was missing since his father's arrest. He said: 'We've seen other people with their parents... seen how they enjoy themselves, how they're so close to them. 'It's like there is a part of our heart that is missing because we've been yearning for him to come home for many years and nothing's happened yet.' On July 4 - Independence Day - a host of Hollywood stars, musicians and politicians called on Mr Obama to release him. In an open letter to the US president, actors including Ralph Fiennes and Sir Patrick Stewart and musicians such as Peter Gabriel joined mounting calls for him to be freed. Advertisement

Yesterday the Government stressed it had ‘one of the most robust and effective systems in the world to deal with suspected terrorists and those suspected of engaging in terrorist-related activity and we will continue to do all we can to protect people in Britain and around the world from the threat of terrorism’.

Clive Stafford Smith, director of legal charity Reprieve and Mr Aamer’s lawyer in the UK, said his return was great news – ‘albeit about 13 years too late’.

He said the UK must urge the US to put the captive ‘on a plane tomorrow’, adding: ‘British politicians may bombasticate about our “robust and effective systems to deal with suspected terrorists”, but Shaker is not and never has been a terrorist.’

He added: ‘Shaker is intensely grateful to all in the broad church of people who have supported him, in particular the Daily Mail for its steadfast advocacy for basic human rights.’

Former Tory Cabinet minister Andrew Mitchell, who joined a cross-party delegation of MPs to Washington calling for Mr Aamer’s release, said: ‘Credit is due to the many who have campaigned for years for this moment and to the Daily Mail who alone among the British Press took a firm and principled stance on this issue.’

Amnesty International UK director Kate Allen said: ‘Let’s not forget his ordeal at Guantanamo has been an absolute travesty of justice. He is the last UK resident to finally get out of Guantanamo and his return to Britain brings a long, painful chapter to a close.’

Detainees including Taliban and al-Qaida suspects dressed in orange jumpsuits as they sit in a holding area at Guantanamo Bay

Labour justice spokesman Andy Slaughter, who has campaigned for Mr Aamer’s release, said: ‘This is fantastic news for Shaker Aamer, his family and for everyone who has campaigned for 13 years to secure this decision.’

Tory MP David Davis added: ‘I would like to give my commendation to the large number of people who have campaigned for Shaker Aamer’s release, not least the Daily Mail. For them this is a very great vindication.’

In 2001, Saudi-born Mr Aamer was detained in Afghanistan while doing voluntary work for an Islamic charity, his supporters say. He was handed to the US military for money.

US intelligence claimed he financed Al Qaeda and was a key aide of Osama bin Laden who fought in the battle of Tora Bora, an accusation that he vehemently denied.

The Mail has always acknowledged that Mr Aamer has questions to answer over what he was doing in Taliban-controlled Afghanistan when he was first detained. But we argued it was an affront to justice and the rule of law that he was denied a trial in which the charges made against him could be tested.

How the Mail has fought to win him justice

By Sam Greenhill and David Jones

The Mail took up the cause of Shaker Aamer last year after a damning official report in America lifted the lid on the brutal torture methods used by the CIA in the so-called ‘war on terror’.

This paper has always stressed that Mr Aamer may be a very bad man but since he was never charged or given a trial, every day of his 13-year incarceration in Guantanamo has represented a grotesque affront to justice and a propaganda gift for terrorism.

The horrifying story of the London father began to emerge after he became the ‘last Briton’ held at the notorious detention camp in 2006.

Human rights campaigners and Mr Aamer’s legal team, led by Clive Stafford Smith, fought doggedly for his release.

The Mail took up the cause of Shaker Aamer last year after a damning official report in America lifted the lid on the brutal torture methods used by the CIA in the so-called ‘war on terror’

In mid-December last year the Mail launched its campaign.

We published a stinging letter demanding action by President Obama from celebrities, civil rights campaigners and politicians. The letter called on David Cameron to ‘pick up the phone’ to the US President and bring Mr Aamer home.

It was signed by actress Juliet Stevenson, actor Mark Rylance, Roger Waters of Pink Floyd, TV presenter Janet Ellis, her singer daughter Sophie Ellis-Bextor and a host of MPs from across the political spectrum.

The Government has since been embarrassed by a series of failed attempts to get Mr Aamer released. In January, Mr Cameron did raise the matter when he met President Obama at the White House, and was told the US would ‘prioritise’ the case. Yet a month later, US Defence Secretary Chuck Hagel admitted the case had still not crossed his desk.

In March, Amnesty International delivered a 32,000-signature petition to Downing Street, and MPs questioned whether the US was secretly negotiating with Saudi Arabia to transfer Mr Aamer there.

MPs began to believe Mr Aamer would never be released because the US did not want him to expose shocking levels of brutality inside the camp. In 13 years at Guantanamo, he was regularly tortured both mentally and physically, being beaten at least 315 times.

Guantanamo Bay detainee Shaker Aamer with two of his four children, son Michael Aamer and daughter Johninh Aamer

A dehumanised figure known simply as Detainee 239, he has been entombed for 22 hours each day, without even a pen or book for stimulation and in a cell so small that its white concrete walls are barely an arm-span apart.

He has routinely been kept in solitary confinement as a punishment for ‘non-compliant’ behaviour. There were suggestions Britain might be happy to see him remain locked up, as he says he was tortured in the presence of British agents.

Far more damagingly, while being held at Bagram airbase, near Kabul, he claims he was privy to a dark episode said to have prompted the US invasion of Iraq in 2003 – when interrogators tortured a man who ‘confessed’ that Saddam Hussein’s henchmen had trained Al Qaeda to use chemical weapons.

In June, the Mail revealed that the US feared Britain would struggle to stop Mr Aamer ‘returning to the battlefield’ if he was freed. But this week when it emerged that a Saudi accused of being Osama Bin Laden’s bodyguard had been freed while Mr Aamer had not.

Saudi-born Mr Aamer studied in the US and worked as an interpreter for the US military during the First Gulf War. Afterwards he moved to London and married Zin Siddique, whose father was the imam of Battersea mosque. In 2001, months before the 9/11 attacks, they moved to Afghanistan.

US intelligence claims Mr Aamer was a personal interpreter for Osama Bin Laden and led a band of Al Qaeda fighters. His family denies this – but he was never given his day in court to defend himself.

When he finally returns to British soil, he will be able to speak freely.