The Archbishop of Canterbury has called on the UK Church to re-commit to unity across ethnic divides, 50 years after Martin Luther King's famous 'I have a dream' speech.

Speaking at the official opening of the Evangelical Alliance's new home in Copenhagen Street, King's Cross, London, today, Justin Welby urged the Church to resist the temptation to create an "us and them" divide between ethnicities.

"It's a very good, but unforeseen thing that we're here on the 50^th anniversary of that extraordinary speech which still brings tears to my eyes when I hear it," Archbishop Justin Welby said.

He added that Martin Luther King did not speak exclusively against many of the evils about which he was campaigning, but "out of Christian faith".

"We are not against things. We are in favour of things. So the key phrase we remember is not a condemnation of the racism or the terrible Jim Crow laws that existed at that time but what we remember is the positive: I have a dream.

"The Evangelical Alliance is an alliance and in the past I suspect that when it started… that there would have been a certain amount of it being an alliance that was against because that's how Christians worked in those days. I rather suspect that the thought of an Archbishop of Canterbury speaking to it would not have been very welcome. Yet today we come knowing that we are one people, brothers and sisters in Jesus Christ.

"And that is the most extraordinary work of the spirit. Alliances must be seen as for. One of the things that I think is most noticeable where we make a bad impression in society at the moment is when we're seen as against things. We come across too easily as negative. We don't intend to, but we do. What is so impressive about what is going on here [at the Evangelical Alliance] is that this is for what the Church is for: It's for foster children, it's for adoption, it's for bringing the Church together as one people. We are an alliance that has to be for.

"Why do we need an Evangelical Alliance? We need it because it is too easy for the Church to be comfortable in separation; like a bad marriage where the couple has drifted apart but not to the point of divorce. They may not even notice that the separation is growing and deepening. The Church can fall into that trap. And the Evangelical Alliance need to be those among many who wake us out of any comfort in disunity because disunity – visible disunity – is contrary to the express will purpose, calling and command of God."

Archbishop Justin Welby said though that there was still a long way to go for the Church to be united across ethnicities.

"Almost all progress in the Church has to begin with repentance," he said. "We need to start by acknowledging that we have been – and continue to be – mired in racism in one way or another."

He acknowledged however that the racism is less overt now and that it had changed much for the better.

"However, we are a long way from where we need to be. We at the Church of England are quite open about that… We come to a God who isn't remotely interested in our ethnic background. The Church spent hundreds and hundreds of years persecuting Jewish people when the founder of our faith was Jewish. But God is someone who is utterly indifferent about what ethnic background someone is from. In fact, quite the contrary, He gave His son to break down those barriers."

Speaking at the opening, Rev Yemi Adedeji – director of the Alliance's One People Commission – spoke of the organisation's aim to cross ethnic divides, while celebrating diversity and promoting unity. 

Rev Adedji said: "Martin Luther King exactly 50 years ago stood there and said he had a dream; a dream where one day brothers and sisters from everywhere – black and white – will come together and they will eat on the same table and they will share fellowship together and they will be one in Christ.

"Today, as we open this building the One People Commission wants to share these words with you; that we have a dream. And the dream for us as evangelicals in the UK is that in years to come for us there will not be one majority Church but there will be one Church that has all ethnicities together in Christ doing what we have been called to do. Our dream is that we will be Christ-centred and have a Christ majority. That is our passion."

Archbishop Justin added: "We must also acknowledge that we are people who are sinners. Whoever we are, wherever we're from, there is a consciousness of 'us and them'. That's what people do when they get together – work out who they're not as well as who they are. We have to set up our church structures to combat that.

"It is as we come to God that these differences disappear. That's why my highest priority in my own life and ministry is a renewal of prayer and communities of prayer because it's when we come close to God that we are convicted of these things and we know that we need to repent."

The Evangelical Alliance, which started in 1846, moved from its former home in Kennington to its new purpose-built resource centre in the heart of the King's Cross regeneration area earlier this year.

"We believe God is the one who has provided for us," said Steve Clifford, general director of the Alliance. "This is a place that we very much want to dedicate to God, to His service, to the service of His Church, to a place where He is glorified in this environment where we are able to work together."

The Evangelical Alliance's membership includes 3,500 churches, 24,000 individuals and more than 700 organisations.

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Image by Alex Moyler