Sue Macgregor with Tony Baker on BBC Radio 4's Today programme: Attacks have doubled

The number of attacks has more than doubled over the last 10 years.

The Arson Prevention Bureau says family and race rows and criminal feuds are among the most common motives for the attacks.

The bureau reports that they cause 65 deaths and 2,000 injuries every year in Britain.

The fires cost an estimated £55m a year in insurance.

The bureau said 42 homes are thought to be set alight every day and the latest figures from 1997 showed there were 15,500 attacks on homes, compared with 7,600 in 1986.

But the bureau is mystified about the large increase.

Bureau chief executive Tony Baker said the figures were "very disturbing".

He said: "The diverse motives of arsonists means that no home is immune from an attack."

He told the BBC that the bureau was carrying out further research on the connection between mental illness and arson.

More security for homes

That report will be published later this year.

Bureau spokesman Malcolm Tarling said householders could help protect themselves from attack by installing alarms, locking doors and windows and having a strong front door.

"We are not talking about making homes into fortresses, we are talking about basic security," he said.

"Arson is relatively easy to start, it's extremely destructive, not just in damage to property but far more serious is the loss of human life."

The report comes a month after a family of seven died in an arson attack in Chingford, Essex. A man has been charged with murder.

The figures do not include attacks on businesses, in which fraudulent insurance claims make up the highest proportion.