Effective evangelism must be rooted in the belief that God is creator, owner, sustainer, director and redeemer. This was the message from the Christian Medical Fellowship during a day course in central London on Wednesday to help nurses and medical workers find the confidence they need to share their faith in the workplace.

"Nurses are often completely unsupported, lonely and pressured," said Annie Leggett, pastoral worker at City Evangelical Church in Birmingham. "It is a tough profession to be in as a Christian."

Leggett, together with Alex Bunn, CMF Southern Students Team Leader, tackled some of the barriers to effective evangelism as part of CMF's "Confident Christianity" course.

Ms Leggett said that although many Christians were "despondent" about going out to share their faith in Jesus, a change in perspective could give them the confidence they need to step out of the church and testify.

"If we haven't understood what God's role is and what our role is in evangelism, then evangelism probably will be an unhappy experience," she said.

Thinking of God as creator, owner, sustainer, director and redeemer would help Christians "see the bigger picture" in their evangelistic efforts.

"God is working and has this salvation plan that He has been working from the beginning of history right the way through to the end, and He is going to return and finish this world and bring a new one. And the way in which He is drawing people to this new world is through us lot," said Ms Leggett.

"For whatever reason, God has chosen people like you and me to be His instruments to share the Gospel and bring people to redemption."

She added: "God is in control of history and our lives. Evangelism is His work and we are His instruments in this work and that is what we need to keep reminding ourselves of."

Leggett and Bunn said that Christians need not be discouraged by the popularity of worldviews such as atheism and relativism but instead use them as openers to conversations about the truth of the Gospel.

"Sometimes in order to talk about the Gospel we need to shut up about the Gospel," said Bunn.

"In order to talk about Christ we have to engage with people where they are, using language that they are familiar with and ask some good questions and once you start asking good questions people begin to see the tension between reality and the worldviews they are plugged into.

"It's about taking people from the 'truth' they know to the truth they don't know," he said.

Leggett added, "We have to help somebody see that what they believe in is not as logical as they thought it was.

"If you can get them to face that wall then there is an opening there for you to start explaining the truth, the Gospel."