The heartbroken vicar of a Grade II*-listed church destroyed during a fire said forensics may never find out what triggered the blaze.
Reverend Kate Harrison held a defiant service outside the burnt-out shell of the church after a towering inferno ripped through, caving in the roof, on Thursday night.
Dozens gathered for a Candlemas Eucharist service on Sunday in the shadow of the church using a cross made from pieces of burnt timber pulled from the building.
She told the BBC: “The forensic services are going to be looking at trying to discover what caused the fire but we have been warned that we might never know.
“It’s really sad, it’s like a bereavement what’s happened here and I would like answers, I would like to know what happened.”
She promised to rebuild the church that had already had its spire partially destroyed after being struck by a German bomb in 1941 during World War Two.
Ms Harrison told the Standard: “I’m absolutely heartbroken. That building has served the Christian community for 175 years. It’s our base where we have been reaching out, helping people, loving people.
“It’s a wonderful beacon of hope and to see it suffer in crushing devastation is completely heartbreaking.
“But it is a building, not the church. The church is the people and our work will carry on, our love will carry on.”
It appears the floor and walls decorated with ornate gold mosaics of Bible passages were destroyed in the blaze.
A local mother told the Standard of the panic she felt as she grabbed her children and fled her home as the fire threatened to spread to her home.
She said: “The clouds of white smoke were really dense and thick and could be seen rising up to the sky and then being blown onto the firefighters by the wind and then blown down toward Maida Vale. I’d never seen anything like it.
“I began to see bright orange flames flicker, which increased until I could see an almighty and vicious fire ravaging through the roof of the church.
“In a state of rising panic, I told my husband we needed to grab our two children, who were asleep, and get out.
“As we left we stood briefly at the front door, watching with sadness, as the front of the Church glowed bright orange from the raging fire. We could hear the loud crackling of the burning as though it were an almighty bonfire.”
She added: “I went to look at the church today and it is a shell. The spire is black and slightly crooked. The locals are devastated. Churchgoers have lost their place of worship. For a decade mothers, fathers, babies and toddlers have enjoyed daytime classical concerts of live musicians in that church.
“Now I can see people sitting in the calm church grounds surrounded by magnolia blossoms and other beautiful flowers. It is a real blow to the community.”
The National Churches Trust has described St Mark’s as an “architectural and historical treasure”.
The building has links to author Lewis Carroll and Queen Victoria’s son Prince Leopold and is near Abbey Road Studios and Lord’s cricket ground.
