Deeply concerned that the world's most notorious drug kingpin, Joaquin "El Chapo" Guzman, could escape for a third time, Mexico has beefed up security at his prison, reinforcing the floor of his cell and placing a guard on his door 24/7. Guzman, captured some six months after a brazen prison break via a mile-long tunnel that burrowed right up into his cell, is now being held in isolation in another part of the Altiplano prison .

The improved security measures also include reducing the number of inmates, quadrupling the number of cameras on the site and moving Guzman randomly, without warning, to different parts of the prison, officials reported. Armoured vehicles and light tanks stand guard outside the prison walls, while security forces man sand-bagged checkpoints beyond the gates of the prison, which is about an hour from the capital.

Local media said cells in the prison had been fitted with electronic sensors, additional CCTV cameras and – in some cases – a mesh of steel bars to reinforce the floor and stymie any efforts to tunnel out. An interior ministry security official, who has visited the jail on various occasions, said the problem with housing kingpins like Guzman was that they could easily buy off the entire prison staff.

In a prison break worthy of Hollywood, Guzman's accomplices apparently obtained the plans to Altiplano and during his 17 months inside built a tunnel fitted with a tiny rail system mounted with a motor bike that he then rode to freedom. In 2001, Guzman bribed guards to help him escape from a prison near the city of Guadalajara after a previous arrest in 1993. He was recaptured in north west Mexico in February 2014.

President Enrique Pena Nieto's government says it plans to extradite Guzman to the US, where he is wanted on an array of charges including drug trafficking, but officials have cautioned the process could take anything from 1-5 years.

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