An electrical fault caused a fire at a complex of elderly people's homes in Maidenhead.
The fire service have started an investigation into details of what caused the potentially lethal blaze at Brill House in Cox Green.
Flames rapidly spread from the ground floor of the Mercia Road property up through the building and across the roof.
Firefighters had to rescue 10 pensioners and evacuate a further 21 residents from the two-storey sheltered accommodation block.
They were called out at 1.40am this morning after smoke set off the fire alarms. More crews had to be called in from Reading, Slough and Langley and about 40 officers were involved in total.
Two pensioners were treated by paramedics but no serious injuries were caused and no one was taken to hospital. All the residents are now staying with family or in a hotel.
Royal Berkshire Fire and Rescue Service's chief fire officer Iain Cox (pictured) said: "It's quite clear that some form of electrical fault, which we are still investigating, has started quite a severe fire.
"Fortunately everybody was evacuated either by ourselves or through the efforts of the staff.
"People were checked over and fortunately nobody needed to be taken to hospital so that from that side of things it's been a fortunate incident in that nobody was hurt.
"We hope to get some people back into parts of the building today."
There is fire, smoke and water damage to about 70 per cent of the building which was built in the 1970s.
Clean-up crews from the fire service and building owners Housing Solutions are currently on site.
Group chief executive of Housing Solutions John Petitt was at the scene this morning.
It is the first serious fire he has dealt with during his 17 years at the company.
He said: "It's been a very traumatic experience for residents.
"What we are pleased about is that we were able to evacuate everybody safely.
"We are in touch with the residents today and waiting to hear if we can get into the building at all, assessing the damage and talking with the families about whether they can move back into Brill House or make alternative arrangements for their accommodation."
Click back later for a video report
Top Ten Articles
CCTV images have been released of men police would like to speak to in connection with a homophobic attack on a couple as they took a train home from a Valentine's Day meal.