The cause of the horrific blaze at Grenfell Tower in west London has yet to be established – but several theories have begun to emerge over what may have caused it.

On Friday morning, the official death toll stood at 17 – but this is likely to rise as recovery teams continue their search of the tower's smouldering wreckage.

As the names of those missing in the inferno begin to emerge, so too are the questions over how it could have ever happened in the first place.

Residents who escaped the towering inferno claimed fire alarms did not sound and they were told to "stay put" in their flats.

It has also emerged an action group claimed their warnings of a "catastrophe" fell on "deaf ears" after highlighting safety concerns three years ago.

Here are the theories on possible causes and contributing factors in the disaster:

A gas explosion?

Residents said refurbishment work had recently been carried out with work on the gas supply to the flats.

Nicky Paramasivan, who was in his seventh floor flat with his partner and child, said that after they fled the explosions from the flats included blue flames, suggesting gas.