Dr Rowan Williams gave the sermon at the evensong service at the cathedral on Sunday evening – keeping a pledge he had previously made to the late Bishop Ian.

The service was intended to have been one of Bishop Ian's last before he stepped down from his role, and Dr Williams had promised to attend.

And despite Bishop Ian's death in May, Dr Williams kept to his word and delivered the sermon at the service on the eve of the patron saint of Peterborough St Peter's Day.

He also met with council, business and religious leaders in the city during the day to discuss the role religion plays in today's society.

More than 600 people packed into the cathedral for the service, more than double the usual amount for a Sunday evensong, and Dean of Peterborough the Very Rev Charles Taylor led the congregation in a round of applause for the archbishop.

Dr Williams spoke of the hard work Bishop Ian had carried out during his time at the diocese.

After the service, Dr Williams said: "The service was to mark St Peter's Day, but also to give thanks to Ian, and the work he did in this cathedral and in the diocese.

"We also offered prayers for the new bishop, when he is appointed.

"It is brilliant to see so many people at a service like this one, and especially to see Christians of all denominations."

Dr Williams also said the lunchtime meeting had gone well.

He said: "We spoke about how important faith is in society.

"I said there was no need for national or local government to fear faith, but, instead, to welcome it."

Today is St Peter's Day, who along with being patron saint of the city is also patron saint of the cathedral and the diocese.

To mark the occasion, there will be a service at the cathedral at 5.30pm.

The service will also act as a thanksgiving for Bishop Ian, and all are welcome to attend.