The Houses of Parliament, Lambeth Palace, Westminster Cathedral and nine cathedrals around the country will all be floodlit red to show solidarity with persecuted Christians around the world.
People wanting to show support for Aid to the church in Need (ACN) and Christian Solidarity Worldwide's #RedWednesday campaign also joined in by wearing red.
A red double-decker bus visited iconic landmarks and places of worship across London as part of the campaign.
Mervyn Thomas, Chief Executive of Christian Solidarity Worldwide (CSW) told Premier why the charity decided to back the campaign.
He said: "We immediately recognised that this was a very simple idea but actually could have great impact to raise awareness for the problem there is around the world, which sadly, the media and general public know very little about."
The campaign follows ACN's recent study called 'Persecuted and Forgotten' which revealed that Christianity is on the brink of being wiped out in certain countries.
John Pontifex, who co-authored the Christian study, told Premier aboard the bus why the colour red is so significant.
He explained: "In church services, red is associated with the blood of those who suffer for their faith.
"So we think of those people who've given their lives ... being executed, or being stoned to death.
Father Aphram Ozan from the Syriac Orthodox Church in Iraq told Premier how important it is to highlight how difficult it is in some parts of the world to be a Christian.
He urged people to pray for those persecuted simply for following Jesus.
He said: "We ask God to help them, to give them strength, to keep their faith in their heart and we pray that this difficult situation will not affect their faith to be thinking about leaving Christianity just because it's difficult ..."
Churches around the world also joined in with the campaign.
Chaldean Catholic Archbishop Bashar Warda of Erbil, in Kurdish northern Iraq will hold a prayer vigil at Our Lady of Perpetual Help Church, which opened last year in response to an influx of Christians fleeing persecution.
In his message, sent to ACN, the Archbishop told the Catholic charity that he intends to floodlight the church red.
Meanwhile, in USA, Christian activists have launched a fresh push for churches and other Christian buildings in the state of Tennessee to floodlight red and there are pledges of #RedWednesday support from countries including Malta and Gibraltar.
In the Philippines, more than 70 cathedrals and other leading churches are also due to floodlight red.
This evening at Westminster Cathedral people will gather for music, testimonies and speeches from Coptic Orthodox Bishop Angaelos of London, Neville Kyrke-Smith ACN's National Director and Mervyn Thomas from CSW.
Listen to Premier's Eno Adeogun speaking to Mervyn Thomas: