The archbishop of Canterbury will give evidence today before a hearing questioning whether the Church of England colluded in and covered up child sexual abuse by priests.

Justin Welby will go before the independent inquiry into child sexual abuse this morning which is holding three weeks of hearings into the diocese of Chichester as a case study for the wider Church.

The inquiry, set up in 2015 under the then home secretary Theresa May, is investigating 13 institutions across England and Wales to examine how they dealt with allegations of child sexual abuse.

In his written statement to the inquiry Welby offered his deep regret at the abuse perpetrated by priests.

'The failures that we have seen are deeply shaming and I personally find them a cause of horror and sadness,' he said. 'That children have been abused in the communities of the church is indeed shameful.'

The Church has upped its spending on safeguarding fivefold since 2014 as it tries to address failings. But despite being predicted to spend more than £5million across dioceses in 2018, the Church still faced more than 700 abuse allegations or concerns against church figures in 2016 alone.

The Church's lead bishop on safeguarding, Peter Hancock, warned before the hearings the Church would 'feel a deep sense of shame' at the evidence that would emerge through the hearings.

'This will not be an easy couple of years – we will hear deeply painful accounts of abuse, of poor response, of "cover up",' he told the ruling general synod in February.

'For too long, the Church has not responded well to those who allege abuse within our church communities. This is now changing and further change is needed.'

The inquiry, now in its third week of hearings, has so far heard damning evidence of the Church's culture of deference that meant allegations against priests went unreported, how the Church's attitude to homosexuality affected it's response to abuse and how child victims were made to feel responsible for their abuse.

Last week Welby praised the 'brave' victims who had come forward and said he was committed supporting the inquiry.

'The Church of England was one of the first institutions to call for the Inquiry and IICSA notes that allegations of child sexual abuse within the Anglican Church are matters of ongoing public concern,' he said in a statement. 'I know that for the survivors who are brave enough to give their testimony, this will be a very difficult time and I pray that the lessons we learn from the Inquiry will help make the Church a safer place for all. I am absolutely committed to supporting the work of IICSA and responding openly and constructively as a witness.'