The family of Stephen Lawrence will gather in Trafalgar Square to mark the 30th anniversary of his death on Saturday.
The murdered teenager’s loved ones will gather for the memorial at St Martin-in-the-Fields church.
Labour leader Sir Keir Starmer is expected to attend alongside the Mayor of London Sadiq Khan.
It comes after Metropolitan Police commissioner Sir Mark Rowley admitted on Friday that the force “did not dig deep enough” to root out racism since Mr Lawrence’s murder in 1993.
The Met commissioner said a failure to robustly confront “cultural and systemic” failings, which were exposed by the force’s response to the murder, had undermined its ability to fight crime, and he pledged to “finally” make the Met determinedly anti-racist.
The Casey Review into the Metropolitan Police published last month found the force to be institutionally racist, misogynist and homophobic in the wake of a series of scandals, including the murder of Sarah Everard by a serving officer and Pc David Carrick being unmasked as a serial rapist.
The bungled original Lawrence murder investigation was hampered by racism and alleged police corruption, which meant it took nearly 20 years for two of the 18-year-old’s five killers to be brought to justice, with three never prosecuted.
Sir Mark said black people still feel “over-policed and under-protected”, with “disproportionalities and systemic biases” in policing continuing.
There remain too few black officers and too many of them face discrimination within the force’s ranks, he added.
He said in a statement: “Thirty years on from Stephen’s murder, we offer our sympathies to the Lawrence family on their unimaginable loss.
“He was a dearly loved son and brother who was taken from them far too soon and in such senseless circumstances.
“Their dignified fight for justice, conducted in the pressure of the public eye with unwavering determination over so many years, continues to be a source of inspiration for us and so many.
“On behalf of the Metropolitan Police, I apologise again for our past failings which will have made the grief of losing a loved one all the more difficult to endure.
“This anniversary, which closely follows the stark findings of the Casey Review, prompts us to pause, to remember and to reflect honestly on how policing has responded to the necessary calls for change that have punctuated the past 30 years.
“This failing has undermined the experience of our increasingly diverse workforce and compromised the trust of Londoners and our ability to protect them from crime.
“We have let black communities down. They feel over-policed and under-protected.
“We are still not sufficiently representative of London, black officers and staff still face discrimination and are not always sufficiently supported to progress within the Met.
“There are disproportionalities and systemic biases in our use of policing tactics and our support to victims of crime.
“We are deeply sorry for these failings.
“The responsibility for righting those wrongs, restoring the relationship with those communities and supporting our black colleagues to succeed starts with those of us in positions of leadership but it continues through every rank and role in our organisation.
“I and the good majority of our officers are resolved to finally make the Met determinedly anti-racist and anti-discrimination of all kinds.”
