Widow Betty Brannan has turned crime-buster after a bogus official conned his way into her Shipley flat and stole keepsake jewellery.

The 75-year-old grandmother, who has since been reunited with the bulk of her treasures, is now backing police to warn other pensioners across the district not to be duped.

Although officers managed to catch the thief and return some of her stolen jewellery tracked down at a pawnbrokers, more is still missing.

"I had a gold watch my sister gave me before she died last year and an oval locket with pictures of my husband inside," she said. "It's not the gold I'm upset about, it's the sentimental value. I was on top of the world to get just a bit of what was taken back but I'd be over the moon to get the rest too."

Mrs Brannan had been cleaning when her doorbell rang and a man flashed an ID card saying he had come to check her electricity supply.

She let him in and he asked her to switch on plugs in the house while he said he was going to check the television plug in her bedroom, where she kept her jewellery and her wallet with £40 pension money. He then said he had to get some test equipment from his car but never returned.

"He'd been gone about five minutes when I went out to see where he was. He had gone but a policeman was coming out of one of my neighbour's flats. The same man had tried to get in there but she'd refused," she said.

"I felt in a trance. I realised straight away he had taken my wallet but it was only later that night I found my jewellery was missing. I felt such a fool to have let him in but he had a card that looked real enough. Thinking back I didn't have a good look at it, certainly not at the picture."

Now she is spreading the word to others urging them to be on their guard.

"People don't need to be scared, they just need to be aware. I'll never let strangers in again, even if they have a card, without ringing first to check they are genuine. I tell people that and that's why I decided to talk to the Telegraph & Argus," she said.

Detective Chief Inspector Terry Long said: "Although we haven't had a serious spate of bogus officials working in the area and these offences are very rare, just one is too many and people have to be aware."

And he added: "The message is just don't let strangers in. Any authentic utility workers won't need to buzz at communal doors to get in because they have their own keys. People should always look carefully at ID cards and if they are still not happy they should ring to check them out. If it turns out they are bogus, they should call 999 straight away."

After the burglary, crime reduction officers from Keighley police teamed up with Council-funded Shipley Anti-crime Partnership and Shipley Community Housing Trust to fit extra door bars and chains on front doors. Crime Prevention Officer Lewis Mackenzie also sent this message to would-be bogus officials: "It's a serious offence and will be dealt with seriously by the court. Don't do it, we're all watching for you."