US civil rights activist the Reverend Jesse Jackson said stemming the flow of guns and drugs into the UK's inner cities was "critical".
Speaking in London at the start of a week-long tour of the UK, Mr Jackson said inner cities were a target market and suppliers had to be identified.
He also said more needed to be done to engage ethnic communities in politics.
Mr Jackson is launching Equanomics UK, a programme which will address social problems in inner cities.
His visit is also part of the bicentenary celebrations marking the abolition of the UK slave trade.
Speaking at a press conference hosted by Labour MP Diane Abbott, Mr Jackson said: "Those guns do not emanate from impoverished areas, they end up there because they are a target market.
"They do not grow these drugs in inner city Manchester or Liverpool or Brixton.
"We need to know where the guns are coming from... and who is profiting from them. That is critical to security and stability."
He criticised those who see "more value in building jails rather than schools".
Mr Jackson said: "You pay a huge price when society is jilted in such a way as to see more value in building jails rather than schools.
"Pre-natal care and day-care on the front side of life is a better investment than jailcare and welfare on the back side."
He also said the UK's black and ethnic communities should be encouraged to play a bigger role in politics.
"People of colour in Britain should stand proud as creditors, not as debtors - after all, the slave trade was the basis of the economic foundation, the basis of the industrial revolution," he said.
"Work without wages as an act of the slave system meant that the enslaved were the creditors and the slave masters were the debtors."
He added: "The people of colour are under-represented at every level of government."
Mr Jackson also strongly criticised the Iraq war saying: "We have lost lives, money and honour and the circle is simply getting deeper and we are losing our lives and we are losing moral authority.
"Those who led it might have to leave because they are morally bankrupt."
The Equanomics UK programme will focus on wage inequality, poverty, trade policy, and the impact of credit and debt on ethnic communities.
The programme is being spearheaded by the 1990 Trust, which promotes the interests of the UK's black communities, and Operation Black Vote, which seeks to engage more black people in politics.
Mr Jackson will visit Bristol, Birmingham, Leicester, Nottingham, Liverpool, Manchester, Sheffield and Bradford during his tour.