Some of London's prominent landmarks will tonight light up in blue, white and red -- the colours ofthe French national flag -- to pay tribute to the 17 people killed in the Paris terror attacks.   

The famous Tower Bridge, Trafalgar Square and National Gallery in central London are to be lit up with blue, white and red colours.

The show of solidarity will coincide with British Prime Minister David Cameron's visit to Paris to join other world leaders for a mega unity march. 

UK Home Secretary Theresa May has also joined EU interior ministers at a meeting to discuss the response to the attacks.   

Cameron earlier tweeted to say he was on his way to Paristo "march with the French people". "The #CharlieHebdo murders will not crush our spirit orour values," he said.