Fire experts investigating the outbreak of a blaze which ripped through a city centre block of flats are focusing their probe on a boiler in a utility cupboard.

At least 30 homes are thought to be damaged or destroyed in the fire at Canterbury's Tannery development and parts of the building are set for demolition.

It's believed 16 of those properties are thought to have "dramatic" damage.

National housing developer Bellway Homes, which built the wooden-framed block around ten years ago, has also launched a "full inquiry" this morning.

Canterbury fire watch manager Sheridan Hudson-Peacock said: "The exact cause had not yet been established but the seat of the fire is suspected to be a small airing cupboard in which there was a boiler .

"The investigation will want to determine how what started out as a small fire in one flat managed to spread so much more rapidly than would have been expected.

Video: How firefighters tackled the blaze

"It really challenged the resources we had in the first instance at the scene. I expect that building control at the city council will also want investigate the fire protection measures between the properties and look at the planning details that would have had to have been signed off."

Crews are still at the scene today investigating the cause and spread of the fire which ripped through a block of city centre flats on Saturday.

Miraculously no one was hurt in Saturday's fire, though many have lost their homes and worldly possessions.

A spokesman for Bellway Homes said that bosses of the Newcastle-based company had this morning launched a "full inquiry" into the circumstances of the fire.

"We're just grateful that no one was hurt," she said.

The firm was awaiting the outcome of investigations into the cause, she added.

Dozens of people last night spent a second night away from their homes after the blaze, but Rheims Way has now reopened to traffic.

Creine Mill Lane North is now open in both directions, but Old Watling Street is closed from the junction with Creine Mill Lane North and Tannery Way North.

Demolition work has started at the Tannery estate in Canterbury, where at least 30 homes are thought to have been destroyed or damaged by the blaze.

Firefighters have been searching for hotspots using thermal imaging cameras, and demolishing and removing unstable parts of the building.

Onlookers said heavy plant vehicles were being used to tear chunks from the building in Creine Mill Lane North.

Rheims Way was closed from the London Road roundabout to Wincheap but reopened on Sunday night.

Age UK in Castle Row was used as a temporary evacuation centre on Saturday night and this morning Canterbury City Council opened a rest and information centre in Westgate Hall.

The council has received food, clothing, toys and bedding from Canterbury residents keen to help the families that have lost their homes but are now asking generous donors to stop.

Canterbury City Council said it a statement yesterday: "We are very sorry but we won't be able to let people who have been evacuated from their properties return to them tonight for safety reasons.

"There will be accompanied access to some properties to collect some essential belongings and if you are affected and haven't yet been in touch with us yet please call our emergency line on 01227 862288."

Celia Glynn-Williams, head of communications for Canterbury City Council, praised the city's universities for being especially helpful in providing shelter for those affected by the fire, with a great level of support also shown from residents.

She said: "We have been trying to find accommodation for people - they have been asking if they can go back to their homes, but we had to make a decision on what was best for their safety.

"We have been speaking to Kent County Council and Rheims Way towards the Wincheap roundabout may remain closed tomorrow until the fire is absolutely out.

"The response by local people has been fantastic - they have been very generous in offering assistance such as clothing and toys.

"We've had Aldi supermarket offer free water for crews working in the blistering heat yesterday and McDonalds has helped with meals at Westgate Hall where the shelter has been set up."

The blaze started at about 2pm in the utility room of a top-floor flat in City Wall Avenue and quickly spread to neighbouring apartments.

Kent Fire and Rescue Service crews worked overnight to deal with hotspots in the roof void from a height vehicle.

At 3.45am firefighters went back into the building's second floor to deal with hotspots.

They are monitoring temperatures in the hotspots and working to stabilise the structure.

A council statement said: "Thank you for all the kind donations to Age Concern but they have more than they can cope with at the moment.

"Please don't take any more there at the moment and we promise we will post up any further requests. Your kindness and generosity has been fantastic. Thank you."

Velia Coffey, deputy chief executive of Canterbury City Council, said the authority had worked closely with emergency services and organisations including St John's Ambulance, Red Cross and the WI to respond as quickly as possible to the incident.

Speaking at Westgate Hall, which has acted as a shelter point for affected families, she said:

"People are obviously very shocked about what has happened to them, especially as some of them appear to have lost everything.

"But they are happy with what we have been able to do for them in terms of support we have been able to offer their families.

"We have had around 30-40 people come to us this morning - some of their homes are uninhabitable, some properties will be habitable once some work has been done on them.

"We are extremely grateful to the University of Kent and Canterbury Christ Church University for opening up their halls of residence for families affected, which we understand could be for up to two weeks.

"We will also be approaching the local hotels as well. We are aiming to assist those who have been seriously affected as soon as possible."

On Saturday crowds gathered at the scene in shock at the scale of the fire, with emergency services still arriving three hours after it started.

Traffic gridlock affected the city, with the immediate area sealed off by police.

Daniel Gower, who owns a property in an adjoining block in Creine Mill Lane North next to where the fire took hold, praised police for rescuing his dog from the site.

The 26-year-old was out in Herne Bay when the blaze took hold, but he had left his faithful friend Tia at home and received frantic calls from friends and family regarding his pet.

Mr Gower, a builder who had worked on developing the Tannery site, said he was also dismayed to see neighbouring properties that he had helped construct so badly damaged.

He said: "I was out with my partner this afternoon when I got about 20 million calls all coming through about this at the same time.

"My first thought was for my dog - I broke down in tears when I saw she was ok, she definitely smelt of smoke and police must have done very well to break the door down - they are thick re-enforced oak fire doors, so thank you to them.

"It's strange how I helped build this in 2005 and 2006 and now to see it like this as they had been well put together.

"My partner Danielle was the first person to move into one of the flats in the road and I am worried for cousins and friends of mine who own places along from where the fire is.

"Everyone is very close to each other there."