The Notting Hill Carnival began today with the colourful and messy J'ouvert parade - a Caribbean tradition

Notting Hill carnage: Four revellers stabbed at Europe's largest carnival as police use new face-spotting computer system to try and keep thugs away amid day of colourful celebration 

• The Notting Hill Carnival began today with the colourful and messy J'ouvert parade - a Caribbean tradition
• Revellers took to streets, throwing paint, mud, chocolate or powder at each other while dancing to music
• It is said the tradition recognises the need of humans to let go of daily worries, if only just for a short time
• Later in the day, young performers with flamboyant costumes danced to music in the Children's 
• Four people have been stabbed in the street in a series of knife attacks which have overshadowed the first day of the Notting Hill Carnival celebrations in London.

One man is in a critical condition and fighting for his life while three other victims, at least two of whom are male, were also taken to hospital. Scotland Yard said they were awaiting an update on the condition of the victims.

Earlier today thousands of partygoers took to the streets to honour the carnival, an ancient Caribbean tradition in a surge of colour and music.

Shortly after sunrise at 6am, early morning revellers got the first street party of this year's event underway – and then threw paint, mud, chocolate, powder and even oil at each other while dancing to music. 

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A horror stabbing incident has overshadowed the Notting Hill Carnival celebrations in London – which has seen thousands of revellers take to the streets to honour an ancient Caribbean tradition in a surge of colour and music

Police and forensic experts were pictured at the scene, although Scotland Yard is yet to release details about the stabbing

A woman was covered in purple paint while walking with friends brandishing paint guns at the Notting Hill Carnival

Revellers start the day's celebrations with the J'ouvert parade at the carnival's opening event celebrating Caribbean tradition

A man smeared in oil shows his best moves. The event can use different decorations including paint, powder and mud

The man covered in oil sat in a kiddy pram with a landline telephone - presumably not plugged in - during the street party

The man covered in oil was must have been looking for a shower after hamming it up at the street party this morning

Police have been very visible on the opening day of the Notting Hill Carnival following terror attacks in other parts of Europe

One attendee (left) held a paint gun as he walked the streets of Notting Hill while others (right) were the target of the attacks

Police had a heavy presence at the carnival as well as officers with special skills for recognising the faces of offenders

It was messy start to the day for these revellers, who were wide awake for the traditional sunrise parade through Notting Hill

Some of the attendees will have a hard time getting clean in the shower later after their efforts in the colourful parade. This man was using oil to decorate himself and friends

Revellers arrive on the first day of the Notting Hill Carnival. Almost one million people are expected over the two days

A woman is splattered with paint from a paint gun. She came dressed for the occasion - and a quick clean-up afterwards

One man (left) preferred a giant fake snake to decorate his body instead of paint and flour while banging a cowbell. Another man (right) preferred some face protection from the paint fights