The alleged mastermind of the 2008 Mumbai terror attack which left 166 dead has been released on bail, Pakistani officials revealed.

Zakiur Rehman Lakhvi was allowed to leave Adiala Prison in Rawalpindi late on Thursday.

His release was slammed with Indians calling it an 'insult' to the victims of the three-day onslaught, which was blamed on the banned Pakistani militant group Lashkar-e-Taiba (LeT).

Pakistani security personnel escort Zakiur Rehman Lakhvi, the alleged mastermind of the 2008 Mumbai attacks, as he leaves court after a hearing in Islamabad on January 1

LeT's charitable wing, Jamaat-ud-Dawa (JuD), confirmed Lakhvi's release.

A senior JuD official said: 'Zakiur Rehman Lakhvi has been released from jail. He is free now and in a secure place. We can't say exactly where he is at the moment for security reasons.'

Another official said Lakhvi would receive a hero's welcome when he arrived at JuD headquarters.

It comes after nearly four months of wrangling over Lakhvi's detention after a judge granted him bail in December, sparking an angry response from New Delhi.

Pakistan's government slapped Lakhvi with a series of detention orders but judges repeatedly cancelled them.

On Thursday the Lahore High Court ordered his release, conditional on a two million rupee (32,000 U.S. dollars or £22,000) bond.

India has long seethed at Pakistan's failure either to hand over or prosecute those accused of planning and organising the Mumbai attacks.

A spokesman for India's home ministry, who asked not to be named, condemned Lakhvi's release.

They said: 'This is a very disappointing announcement. An insult to the victims of the 26/11 Mumbai attack. The global community should take serious note of Pakistan's double-speak on terrorism.'

Pakistan foreign ministry spokeswoman Tasneem Aslam blamed India for delaying the case.

Flames and smoke billow from the roof of the Taj Mahal Hotel in Mumbai on November 27, 2008 during an attack by militants

Smoke and fire billowed out of the Taj Hotel during the attack. Elite Indian commandos fought room to room battles with Islamist militants inside the luxury hotel to save scores of people trapped or taken hostage

People duck behind a white fence as gunshots are fired from inside the Taj Mahal hotel on November 27, 2008

Debris and burnt out cars litter the street at the site of a blast in Coilaba, a market in downtown Mumbai on November 26, 2008

A TERRORIST ATROCITY DUBBED MUMBAI'S 9/11 The horror of the Mumbai carnage played out on live television as commandos battled around ten heavily armed gunmen, who arrived by sea on the evening of November 26, 2008. The gunmen carried out twelve coordinated shooting and bombing attacks lasting four days, and killing 166 people. They targeted guests at two five star hotels, a Jewish centre and commuters at the city's main railway station. It took the authorities three days to regain full control of the city. Nine of the gunmen were killed. Advertisement

She said: 'Inordinate delay in extending cooperation by India complicated the case and weakened the prosecution.'

Lakhvi and six other suspects were charged in Pakistan - but their cases have made little progress in five years.

Delhi has long accused Islamabad of prevaricating over the trials, while Pakistan has alleged that India failed to give it crucial evidence.

Lakhvi's initial bail order in December prompted an angry response from Indian Prime Minister Narendra Modi, who said it came as 'a shock to all those who believe in humanity'.

Pakistani analyst Hasan Askari said he was at a loss to understand why the case had not been resolved.

Map detailing the 2008 Mumbai attacks and a photo of Zakiur Rehman Lakhvi, the man suspected of organising them

He said: 'The government must settle this case once for all and face the international community.

'It's strange that this case has not been decided since 2009.'

New Delhi has long said there is evidence that 'official agencies' in Pakistan were involved in plotting the attack.

Islamabad denies the charge but JuD, seen as a front for the militant LeT and listed as a banned terror outfit by the United Nations, operates openly in the country.

Pakistan has long been accused of playing a 'double game' with militants by supporting groups it thinks it can use for its own strategic ends, particularly in disputed Kashmir.