4 January 2013 Last updated at 02:55 ET

Stephen Lawrence murder: 20th anniversary to be marked

Stephen Lawrence was an A-Level student

The mother of murdered teenager Stephen Lawrence has begun a campaign to mark the 20th anniversary of his death.

Doreen Lawrence said she wants to ensure no other family has to go through what she endured.

The campaign will include talking to new police commissioners and a memorial service on 22 April - the date Stephen was killed in Eltham in 1993

The announcement comes exactly a year after Gary Dobson and David Norris were convicted of his murder.

Other events will include a concert planned for April, a criminal justice lecture, an annual memorial lecture and a gala ball.

The memorial service will be held at St Martin in the Fields church in Trafalgar Square.

Mrs Lawrence, who founded the Stephen Lawrence Charitable Trust, said: "It is hard to believe that 2013 will mark 20 years since Stephen died.

Fairer community policing

"This time last year we faced the conviction of two of Stephen's killers and the relief I felt then has stayed with me through the extraordinary year that was 2012.

"Despite this, our focus has to be on the next 20 years.

"There is more to be done to get justice for Stephen and to ensure that no other family has to go through what we endured."

Mrs Lawrence said the trust would campaign for fairer community policing.

She also continues to press for the tracing and arrest of others involved in the murder of her son.

During Dobson and Norris's trial, the court heard a gang of five or six white youths set upon the A-level student in Eltham, south-east London.

The Metropolitan Police faced criticism of the original investigation into Mr Lawrence's death.

A public inquiry branded the force institutionally racist and claims were made by Mr and Mrs Lawrence's lawyers that some officers were influenced by Norris's former drugs baron father.

The breakthrough in the investigation came when a cold case team of forensic scientists found tiny traces of blood, hair and fibres on clothing seized from Dobson and Norris's homes.