Greggs the bakers has apologised for placing a sausage roll in the Nativity scene to advertise its Advent calendar.

The chain faced a call for a boycott from the chief executive of the Freedom Association who claimed the product was "sick" and the Newcastle-based firm had insulted Christianity in a way it would "never dare" other religions.

The £24 advent calendar is available in selected shops and behind each door is a voucher for one of its treats.

The firm's decision to use a publicity image of the Three Wise Men around the crib with the baby Jesus replaced by a sausage roll has caused controversy.

A Greggs spokesperson said: "We're really sorry to have caused any offence, this was never our intention."

Simon Richards, CEO of the Freedom Association, called for a public protest.

He tweeted: "Please boycott @GreggsOfficial to protest against its sick anti-Christian Advent Calendar.

"What cowards these people are: we all know that they would never dare insult other religions!

"They should donate every penny of their profits to @salvationarmyuk."

The Rev Mark Edwards of St Matthew's Church in Dinnington and St Cuthbert's Church in Brunswick said Greggs had been "disrespectful".

He told the Newcastle-based Chronicle: "It goes beyond just commercialism, it's showing a total disregard and disrespect towards one of the greatest stories ever told, and I think people of all faiths will be offended by this."

The advert created a debate on the Greggs Facebook page with a minority of comments complaining about the scene and most people welcoming the product.

Comedian Bob Mortimer wrote on Twitter: "Come on KFC ... show Greggs the way ... put a miniature Jesus in all your Christmas buckets."

And agony aunt Philippa Perry joked in a tweet: "ANYWAY who cheated and opened 24th Dec BEFORE 24th Dec to find this out."