A dog can be a man's best friend. But for Mary Whelan, poodle Lewis serves a more important purpose - he is her ears.

Mary is one of many deaf people who live in a world of silence. Everyday tasks such as hearing the doorbell or reacting to a fire alarm are impossible.

But, thanks to her miniature poodle, Mary has nothing to fear.

"I feel much safer now, especially at night," she said.

Mary, pictured, of Nab Wood, is nearly fully deaf.

"People don't realise how deaf I am because I have good speech but I really cannot hear much at all now," she said.

Four years ago, the charity Hearing Dogs for Deaf People gave her a hearing dog to aid her with everyday household sounds.

"I applied to the charity for a hearing dog and they chose Lewis. He is really well suited to me and tells me when there's someone at the door or when the telephone is ringing by touching my knees," she said.

"He is also trained to warn me if a fire or burglar alarm goes off."

Lewis was trained for 16 weeks at a hearing dogs centre in Selby to recognise everyday noises and warn his owner accordingly.

The dogs, which cost around £5000 each to train fully, often come from rescue centres or are donated to the centre as unwanted pets.

A spokesman for the charity said: "We socialise the dogs by placing them in ordinary homes for up to eight months first and teach them a little bit about basic obedience, housetraining and manners. They then begin their sound-work training."

The dogs can be trained to recognise any sound but the most common are doorbells, cooker timers, telephones or a baby crying.

Ann-Marie Dixon, 35, has just started living alone and is currently applying for a hearing dog. "It is most frightening at night when you cannot hear. A dog will be a big help and will also be a good companion," she said.

A trainer from the hearing dogs charity will shortly visit Ann-Marie to assess which sounds she would like her dog to warn her of. A dog will then be matched to her.