The number of people suffering from dementia in Britain is forecast to grow 38 percent over the next 15 years, incurring huge costs, according to a report on Tuesday.

At present almost 700,000 people in Britain have dementia -- 1.1 percent of the population -- at an estimated cost of some 17 billion pounds a year in care and accommodation costs.

According to research for the society by the London School of Economics and the Institute of Psychiatry, the number of patients is forecast to grow to over 940,000 by 2021 and to 1.73 million by 2051.

Dementia can affect people of any age but is most common in older people. One in five people over 80 and one in 20 people over 65 have a form of dementia.

Symptoms typically include loss of memory like forgetting names of people and places, mood changes and communication problems.

The most common type is Alzheimer's disease, which changes the chemistry of the brain, causing brain cells to die.

Health Secretary Patricia Hewitt, in a follow-up statement, added that research into Alzheimer's has doubling and a new investment into emergency respite care for carers of Alzheimer patients would be introduced.

One Christian organisation, the Methodist Homes for the Aged, already offers older people with centres offering specialist-led nursing for sufferers of dementia.