Thousands of people will join marches across the UK today to demand that no other children should suffer the same fate as Baby P.
Organisers of at least 18 events have used the social networking site Facebook to spread details.
The London march ends with campaigners handing in petitions to 10 Downing Street.
There will also be speeches and prayers in memory of the child.
Baby P suffered more than 50 injuries at the hands of his abusive mother and her 32-year-old boyfriend, and their lodger, Jason Owen, 36.
The injuries came despite 60 contacts the baby had with the authorities in Haringey, north London, over eight months.
Signatures taken during the event mark the last batch of hundreds of petitions supporters have sent to the Prime Minister.
At 3pm, doves will be released followed by final speeches until the event ends at 4pm with Christmas carols.
The Justice March for Baby P events gathered pace after 11 mothers and other women from all over the UK teamed up on Facebook.
The group launched a campaign for "urgent far-reaching changes in child protection laws and social services".
"Please let's stop this happening again and again," the group states.
One of the organisers, mother-of-four Dolly Bartlett, from Newham, east London, said: "Our group is Justice March for Baby P but we are not forgetting babies A-Z."
She said more than a thousand people were expected to join the London march alone.
Crowds were gathering at Millbank at 11am to collect T-shirts and sign petitions before marching to Downing Street at 1pm.
At 3pm doves were being released followed by final speeches until the event ends at 4pm with Christmas carols.
Meanwhile other marches will depart in towns and cities including Plymouth, Leeds, Newcastle, Porthcawl, Coventry, Blackpool and Edinburgh.
The full listing can be found at the Facebook site.
Source: Sky News
Not the turn out they hoped for, but very well done to the girls on Facebook for organising the events around the country and seeing it through. If only Baby P had known this kind of compassion from his parents and the people whose job it was to protect him from his life of agony.
Goodnight, Baby P, rest in peace.