He added: “People come to this museum to learn about the slave trade and much of it is disturbing, but in looking at its legacy, we can add something positive and inspirational to the experience. This is what we hope to achieve with the Black Achievers’ Wall.”

The unveiling followed an afternoon of seminars looking at the progress of the US Civil Rights Movement in the 150 years from Abraham Lincoln to Barack Obama.

One woman who witnessed the unveiling said: “It is nice to see Obama up there and it would be great one day to have a black British Prime Minister on the wall too.”

The new pictures were unveiled to mark US Black History Month and bring to 79 the total of faces that make up the wall.

Achievers already on the wall include Archbishop Desmond Tutu, musician Bob Marley, Dame Kelly Holmes and Liverpool boxer John Conteh.

To nominate a black achiever to appear on the wall, contact National Museums Liverpool via the website www.liverpool museums.org.uk

PETER ELSON gives the acting US ambassador a personal tour of Liverpool – don’t miss tomorrow’s Liverpool Daily Post