This is the astonishing moment a policeman who caught a huge 7ft-long monitor lizard stretched out next to the beast to show its massive size.

The officer arrived with reptile handlers after terrified residents found the 100kg monster blocking the door of their home in Nakhon Si Thammarat province, southern Thailand on March 23.

Homeowner Khun Teerasak initially mistook the creature for a crocodile but as he moved closer he found that it was actually a gigantic monitor lizard.

Reptile catchers and police who arrived at the scene were shocked to see the creature - which suddenly became aggressive.

The team tried catching the massive beast but it was too large and violent. They had to devise a strategy to avoid being bitten by the venomous reptile.

To subdue the lizard, the rescuers and a policeman split up into two teams - one was to approach the lizard from behind, while the other tried to snare it with a noose. The monitor lizard tried to wriggle its neck free, but was eventually wrestled into submission and pinned to the ground before being tied up with a rope to a stretcher.

Prai Ubon, a specialist present at the scene, said: ‘This was the biggest monitor lizard I have ever seen in my entire life. It was 7ft-long and weighed more than 100kgs. I had to take pictures before releasing it somewhere far away from the neighborhood.’

The lizard was taken away in a pick-up truck before being released into the wild. It was unharmed following the ordeal.

Asian water monitor lizards live in canals and ponds in large cities in Thailand where they feed on fish, snakes, frogs and scraps of food left by humans.

In Thailand, all monitor lizards are listed as protected species and are often found in rivers and canals even in urban capital Bangkok.