Dynamic US speaker and author Dr Tony Campolo spoke at a specially convened JustShare event in central London Friday, building on the theological background behind economic and social injustice.

Dr Campolo, who is a Baptist minister, as well as former spiritual adviser to Bill Clinton and leader of the US 'Christian Evangelical Left', addressed Christians working in London's financial district, challenging their commitment to issues of trade and justice and encouraging them to support policies and practices that lead to a more just world.

He spoke about the different levels- micro, middle, and macro- on how to tackle injustice in today's world, concluding with a powerful note as he urged the crowd to start with the small things.

"If you can't do small things well, don't even think about the big things."

He encouraged them to start by making a difference in a child's life, referring them to child sponsor charity Compassion International.

In his latest book, Letters to a Young Evangelical, Campolo records the recent history of American evangelicalism through World War II, Billy Graham's rise to prominence in the 1950s, and the growth of megachurches in the US.

According to Campolo's book, more than 80 per cent of evangelicals voted for Republican candidates in the 2004 elections, however, he rejects that all evangelicals align themselves with the religious right.

He wrote in his book: "We don't like that designation because it suggests that we are an arm of the Democratic Party in the same way in which the Republican right has become an arm of the Republican Party. We contend that to ally Jesus with either political party is idolatry. The Jesus of Scripture will not conform to the ideologies of any party."

An outspoken campaigner, Dr Campolo is pushing Christians to a greater focus on crucial issues such as poverty and corporate greed.

He will wrap up his UK tour in Herefordshire on Tuesday 27 February.