I WAS getting the shopping out of the car when a harried woman came running up and looked in beseechingly so that I would wind down the window.

She spoke with a low, trembling voice and she looked as if she had been crying. She said she had run out of her house after an argument and that she desperately needed to get from central London to her parents' home in Wiltshire that night.

She had left her money behind in the house after finding her husband with another woman and had spent the last hour asking people if they would lend her enough cash to get the train. She was even more distressed by some of the responses she'd had and said two of the men she'd asked had suggested that she earn it through doing them a sexual favour.

I was horrified to hear such a dramatic tale but not surprised by the indifferent response she'd had.

I invited her into my car in the hope that she would calm down but she remained on the verge of hysteria. She said she desperately needed £40 to cover her tube and train fare but I only had £5 left in my purse. I suggesting ringing my parents, who could bring the money to her, but she seemed to panic at that and said she'd be embarrassed if they knew what she'd been through.

She then appeared to have a brainwave - she would give me her contact details and I could get some money out of a cash machine to lend her. She wrote down her mobile number and address and I gave her my details in return. The bargain depended on me putting my trust in her story. I wasn't sure whether she was for real but, just in case she was, I was going to do it.

She was in her 40s and reminded me of my English teacher at school, and she linked arms with me as we walked to the nearest cashpoint.

Her story made me feel a sense of sisterhood, that I couldn't leave her in her plight, but a part of me recognised that if she were lying, what better way to con a fellow woman. By the time we arrived at the cashpoint I wasn't sure at all.

Anyway, I got the money and, just as I was about to hand it to her I got an overwhelming urge to confront her, to say I knew she was lying. But I didn't. I simply gave her the £40 and saw her walk away, rapidly, before she turned to see if I was still looking. She wasn't walking anywhere in the direction of the tube station to get to her parents' home.

All along, I think I had known I was being done but perhaps I'd gone with it because I believe in people's better natures and it was a test to see if we all need a bit more trust in strangers.

As it happened, she failed the test - I never heard from her again and the number she gave me just rang and rang. A harsh lesson to learn, but I never believe strangers any more.