Justin Welby, the bishop of Durham, is expected to be unveiled as the next archbishop of Canterbury within days as Lambeth Palace prepares to break weeks of silence on the identity of Rowan Williams's successor.

After a selection process shrouded in secrecy and mired in internal wrangling, the 56-year-old evangelical Old Etonian appears set to take over the leadership of the Church of England from Williams, who will step down at the end of the year.

On Wednesday neither Lambeth Palace nor the church showed any sign of wanting to lift the effective news blackout that has characterised the work of the Crown Nominations Commission (CNC) since the end of October, and a spokesperson refused to comment on reports that Welby had officially accepted the job.

But his name is believed to have been passed to Downing Street after it emerged as the preferred option of the 16-member CNC. The prime minister's official spokesman said on Wednesday that Downing Street was expecting an announcement soon.

Other more experienced candidates for the position included John Sentamu, the archbishop of York, Graham James, the bishop of Norwich, and James Jones, the bishop of Liverpool.

But Welby's supporters say that, despite his relatively short clerical career – he was enthroned as a bishop less than a year ago – he remains the best man for the job.

A Cambridge graduate who spent his twenties working in the oil industry, first for the French oil company Elf Aquitaine and then for the oil exploration group Enterprise Oil plc, Welby only took his first steps in the clergy in the 1990s.

He then embarked on a swift rise through the ranks of the church, becoming dean of Liverpool in December 2007 and bishop of Durham in November last year. His experience in business and ethics made him a natural choice to join the parliamentary commission on banking standards earlier this year.

Williams, who is hoping to have a valedictory landmark success later this month when legislation approving women bishops comes before the General Synod, advised whoever does become the 105th man to sit on the throne of St Augustine to take a keen interest in the media. Speaking in Auckland, he quoted the theologian Karl Barth when asked what qualities his successor would need, saying he would be one who preaches "with a Bible in one hand and a newspaper in the other".

He went on: "You have to be cross-referencing all the time and saying, 'How does the vision of humanity and community in the Bible map on to these issues of poverty, privation, violence and conflict?' And you have to use what you read in the newspaper to prompt and direct the questions that you put to the Bible: 'Where is this going to help me?' So I think somebody who likes reading the Bible and likes reading newspapers would be a good start."

Long the front-runner in the succession contest, Welby's potential appointment has prompted intense speculation in recent days, with leading bookmakers Ladbrokes and William Hill both suspending betting after a spike in interest in the bishop of Durham.

The speculation increased on Wednesday when it emerged he had cancelled an appearance on the BBC Radio 4 programme Any Questions that had been scheduled for Friday in Country Durham.