Tower Bridge taking on the colours of the Flag of France in support of the Paris rally of unity. Image: Katie Callin

By Katie Callin

The Tricolore has lit up Trafalgar Square, County Hall opposite the Westminster Parliament and Tower Bridge in support of the rally for unity in Paris.

Thousands of Londoners also assembled in sympathy on the same day as the largest demonstration in the history of France attended by heads of state including the Prime Minister.

The Francophile atmosphere in Trafalgar Square is set against the backdrop of the blue cockerel on the fourth plinth- often seen as an unofficial symbol of France.

Giant blue cockerel on 4th plinth by German artist Katharina Fritsch amid scenes of pro-French solidarity. Image: Katie Callin.

In London the singing and chants echoed those heard in Paris.

A shrine of pens, pencils, ‘Je suis Charlie’ banners and Charlie Hebdo cartoons was created in memory of the victims of this week’s attacks.

Charlie Hebdo shrine in Trafalgar Square on the day of the Paris rally of unity. Image: Katie Callin

It’s estimated several thousand people gathered in central London to sing the French National anthem, and chant slogans for liberty, democracy and freedom of expression.

The French interior ministry has speculated three million people turned out in Paris.

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Prime Minister David Cameron linked arms with world leaders at the head of the rally that was protesting against terrorism, extremism, intolerance of freedom of speech, and anti-Semitism.

He said that the march was inspirational and he and other world leaders agreed it was important to tackle the poisonous ideology behind the murders.

The slogan shared by many was ‘Je suis Charlie, je suis flic et je suis juif’ in memory of the victims of shootings by extremists this week.

Most of the victims were journalists and cartoonists working in the satirical magazine Charlie Hebdo. Three were police officers.

Those killed included a caretaker, four people in a Kosher supermarket and the three islamist extremist gunmen.

The Deputy Prime Minister Nick Clegg was in London’s Trafalgar Square and told Londonmultimedianews reporter Katie Callin that the terrorism threat to Britain would be reduced if there was less conflict in the Middle East.

In London there was a carnival atmosphere. One protester held a fist high in front of Nelson’s column wearing a paper bag declaring ‘Je suis Charlie, Ahmed, Flic, Juif, Republicain…’

Carnival style protest against the killings of journalists, police officers and jews in Paris. Image: Katie Callin.

Ahmed was the forename of the Muslim police officer executed when the brothers Cherif Kouachi and Said Kouachi made their getaway from the Charlie Hebdo headquarters.

Flic is a slang term for police in French.

The blue, white and red of the French republican flag, the Tricolore, was projected on famous London landmarks.

It covered each wing of the National Gallery building on the north side of Trafalgar Square and was reflected in the water flowing in the fountains.

The Tricolore of France projected in Trafalgar Square in support of the Paris rally of unity. Image: Katie Callin

The Mayor of London, Boris Johnson said the people of London stand shoulder to shoulder with Paris.

Mayor of London Boris Johnson’s handwritten message of support for Paris. Image: @MayorofLondon

The light shows at a simultaneous London rally were intended to show solidarity.

The French Embassy in Britain thanked Boris Johnson for organising the support in London.

Earlier Deputy Prime Minister Nick Clegg signed the book of condolence at the French Embassy.

Leader of the Liberal Democrats and Deputy Prime Minister Nick Clegg signs the book of condolence at London’s French Embassy. Image: @France in the UK

Gestures of support have been displayed all over Britain- from the union jack flying at half mast over the Palace of Westminster…

to a flag of France also half mast outside a village post office.

A Flag of France flies at half mast at an English village post office for those killed in Paris terrorist attacks. Image: Londonmultimedianews.com

Audio-slideshow of images and sound from the Trafalgar Square rally and projection of French colours on London landmarks Sunday 11th January 2015.