Church communities and other faith groups are coming together in an act of solidarity with those around the world suffering persecution because of their faith today. The Red Wednesday event co-ordinated by Aid to the Church in Need will involve lighting up Westminster Cathedral and Westminster Abbey in red.
Also being floodlit in red tonight - Wednesday, 23rd November - are religious buildings around the country - including Brentwood Cathedral and St John's Wood Synagogue.
A red Routemaster London bus emblazoned with the words 'Stand up for Faith and Freedom #RedWednesday' is making its way through London stopping at the Imam Khoei Islamic Centre, St Paul's Cathedral, and St John's Wood Synagogue and Westminster Abbey.
The bus set off from Westminster Cathedral and will be waved off by youngsters from the nearby St Vincent de Paul Primary School.
Students from schools in many parts of the UK are marking Red Wednesday by wearing an item of red clothing and holding prayer services and other activities in support of people suffering for their faith.
Coming to London to support Red Wednesday is His Holiness Ignatius Aphrem II, Patriarch of the Syriac Orthodox Church, based in Damascus, Syria, Dr Sarah Bernstein, Director-General of the Jerusalem Centre for Jewish-Christian Relations, Israel and Shaykh Dr Umar Al-Qadri Ameer, Head-Imam of the Al-Mustafa Islamic Educational & Cultural Centre, Ireland.
Tomorrow (Thursday, 24th November), they will be speaking at the launch of Aid to the Church in Need's 2016 Religious Freedom in the World report which assesses the situation for different faith communities in 196 countries - every nation on earth.
The launch will take place in the Grand Committee Room of the House of Commons and will be chaired by Lord David Alton of Liverpool.
Aid to the Church in Need UK National Director, Neville Kyrke-Smith, said: "We hope that the ACN red bus as it travels London on Red Wednesday will highlight the very real and pressing issue of those suffering because they are persecuted today for their peacefully held beliefs."
He added: "We will invite all those, whether Christian or other faiths to attend and show their support for the right of a person to practise their religion in peace".
Describing the plans for Red Wednesday, event coordinator Patricia Hatton said: "We are delighted that a growing number of parishes, schools and groups around the country are pledging their support including Catholic, Church of England and Free Churches who are lighting red."
She added: "We are also inviting everyone, and especially schools, groups, and university students to wear red - as a symbol of the suffering today of people of faith.
"Priests too can get involved by wearing red vestments to celebrate the Feast of St Clement, Pope and Martyr."
Mrs Hatton encouraged people to support Red Wednesday by coming to see the bus and meet those on board and people of different faiths involved in the event.
The Routemaster is due to depart Westminster Cathedral at 11.30am, arriving at noon at the Imam Khoei Islamic Centre. The bus will then travel to St John's Wood Synagogue, arriving at about 12.45pm, before moving on to St Paul's Cathedral around 3pm. Depending on traffic, the bus may stop at Buckingham Palace, Trafalgar Square and the London Eye.
It will arrive at Westminster Abbey at 4.30pm for photographs to be taken with dignitaries including Lord Alton of Liverpool.
The ACN red bus will go on to Westminster Cathedral, where it will remain at from 5pm until 7.30pm. There will be a Mass will be a Mass in the cathedral from 5.30pm.
A Prayer service will be led by Westminster Youth Ministry team in the Cathedral Piazza alongside film and music including Soul Sanctuary Gospel Choir and violinist, Cathy Fox.
Westminster Cathedral will be will illuminated in red from 6.30pm until midnight.