Police have warned elderly and vulnerable people to beware of telephone callers trying to make appointments to visit their homes.

An 86-year-old woman raised the alarm after a bogus gas call.

Dorothy Reader's suspicions were aroused when she got a phone call from a woman who claimed to work for British Gas.

Mrs Reader, who lives alone in Great Horton, Bradford, has her gas boiler serviced once a year as winter approaches.

The woman asked for her by name and checked if she had recently had her boiler serviced.

Then she asked if she could come to check the boiler at a specific time and date.

Mrs Reader said: "I said she couldn't come then because I was going to the hospital. Then she said she would have to leave it for the time being.

"After hanging up the phone I thought, This isn't right.' I have had that maintenance done for more than 20 years and that has never happened before."

Mrs Reader dialled 1471 and discovered the caller had withheld the number. So she called British Gas.

"They said straight away they didn't do things like that," she said. Mrs Reader, a former casting clerk, called the police.

She has home safety precautions, such as an alarm on the front door handle and an alert button which she wears around her neck.

But she was concerned for other people who might not think anything of taking a similar call or answering the door to a stranger.

"There are lots of elderly people who would let someone in. I don't want this to happen to anybody else," she said.

A West Yorkshire Police spokesman said: "Residents should make sure that people have ID before letting them into the house.

"We would support the action that she took."

The spokesman said that people concerned by a telephone call or visit should report it by telephoning 0845 6060606. All reports will be logged and a community warning issued.

Councillor Joanne Dodds (Lab, Great Horton) said: "The message is that people treat anybody on the phone as they do with bogus callers on the door - say no and don't give out any personal information.

"When people ring up they catch you on the hop.

"It could affect anybody, really, not just elderly people, but they are more vulnerable."

e-mail: rebecca.wright@bradford.newsquest.co.uk