For the past two weeks, a Christian hymn has been cropping up in an unlikely place - the protests that have drawn millions of people on to the streets of Hong Kong.

"Hallelujah to the Lord" has become the unofficial anthem of crowds protesting against a controversial proposed law that would allow people accused of crimes in China to be extradited to the mainland.

For Christians in Hong Kong, the hymn is a sign of faith but also of their concerns that it's not only political but also religious issues that are at stake, should the bill ever pass.

The protests were already under way when the tune first started being sung.

But on 11 June - a day before the protests turned violent - a group of Christians holding a public prayer meeting through the night started singing Hallelujah to the Lord.

The hymn was picked up by other protesters - soon even non-Christians were singing it.
The protesters said they sang it hoping it would have a calming effect on police, and would help diffuse tensions.

The song also acted as a political shield, of sorts.

"According to the law, any religious assemblies in public areas are not considered as illegal, so if people sing hymns together, it could actually work as a protection and guarantee that [they] stay safe," said Mr Chow.

"Therefore people started to sing this song to protect themselves."