The Anglican Bishop of Portsmouth, the Rt Rev Kenneth Stevenson, will make his first public appearance for six months at a special, inter-denominational service at Portsmouth Cathedral Sunday 13 May.

Bishop Stevenson is still recovering from a bone marrow transplant he was given in December to combat leukaemia. Doctors are pleased with his progress and he is "regaining strength each day".

He hopes to lead a united service organised by Christians Together in Hampshire and the Isle of Wight, which brings together Anglicans, Roman Catholics, Methodists, Baptists and those of other denominations across the two counties. They will join forces on 13 May to celebrate the work that Christians do together to promote social justice.

Hundreds of worshippers will take part in the service, which will be based on a special liturgy written by John Bell of the Iona Community. It takes inspiration from Christian Aid's work in El Salvador and the example of Archbishop Oscar Romero. There will be music from a united choir and Portsmouth's Salvation Army band, African drumming and a sermon from Matthew Reed from Christian Aid.

"Ten years ago I would have died," he said. "It is a miracle that I'm here at all. The illness has affected the way I think and feel about Christianity and the way I do my job. I don't want to become a leukaemia bore, but inevitably it will colour everything I do for the rest of my life.

"I've been living on the fringes of Christianity for much of the past couple of years, so I feel as though I've been looking at the church from outside. I may therefore need convincing that some things that others think are important are actually as important as all that!

"The other thing about being ill is that you realise how important people are. I haven't missed the big, set-piece occasions so much as the ordinary visits to parishes - meeting the people who would be there whether the bishop was there or not. When I've celebrated the Eucharist in my chapel and prayed for the churches in the diocese, sometimes I've ached to be there with them."

Bishop Stevenson was given the bone marrow transplant from an anonymous Italian donor whose DNA matched his. In February, he went back into hospital for 10 days to fight a virus that his donor had already had.

He will continue to be monitored until the end of 2008. If he remains clear of leukaemia until then, the chances of the disease returning are very small.

"I hope everyone will understand if I don't linger after a service, and that I'm not allowed to shake hands with people," said Bishop Stevenson. "It will take a bit of time to build up my immune system completely - I've done so well so far. And I won't be able to use public transport or visit air-conditioned places until this December."

Next month, Bishop Stevenson's book on the Transfiguration will appear. 'Rooted In Detachment: Living the Transfiguration' was written as he recovered from his first bout of leukaemia last year, and is published by Darton Longman and Todd. He hopes to launch it at diocesan synod on June 23.

Incredibly, Bishop Stevenson also managed to write a second, 150-page book between 8 January and 9 February while recovering from his bone marrow transplant. 'Watching and Waiting: the Riddle of Advent' is a devotional book, and will be published by Canterbury Press in October.

"It's based on eight Old Testament texts that look forward to the coming of Christ," said Bishop Stevenson. "We tend to walk through Advent, but it's an important time and the way those Scripture texts are used in worship show how they contain everything about the Christian faith."