The accounts manager says coins, safety pins, magnets, spanners and even a metal lid from a Vaseline pot can stay on her body for up to 45 minutes without falling off.
When the pulse is at its strongest, she says she can even dance in her living room without them coming off.
For as long as she can remember, she explains, her body has set off car alarms, interrupted the TV signal and blown out light bulbs.
Positive: Mrs Allison was once accused by a cashier of deliberately cursing his till when her magnetism caused it to develop problems
When she was a child, she said, her parents stopped buying her watches because her magnetic field kept interfering with the timing mechanism.
Every person has a subtle electromagnetic field flowing through their bodies – but most of us are unaware of its presence. However, Miss Allison, 50, says she first noticed the effects of her magnetism when she was in a nursery school.
As she grew up she started to keep a diary and realised the magnetic pulses were strongest at the end of each menstrual cycle.
‘People laugh when I put metal objects on my skin and they don’t fall off,’ Miss Allison, of Holloway, North London, said: ‘But sometimes my condition can be extremely embarrassing.
‘On one occasion I had a dreadful experience at the supermarket. When I reached the check-out the till machine started to misbehave and it was obvious I had caused it.
‘The man on the checkout started shouting at me and accused me of putting a voodoo curse on his till.’
Doctors have told Miss Allison that her magnetism may be caused by high stress levels and have urged her to take steps to relax.
During strong magnetic periods she has been advised to grip the kitchen taps as they are ‘earthed’.
She said her one wish was to be tested by electromagnet specialists so she can understand the cause behind her condition, adding: ‘When I was a child my parents knew there was something different about me – but they never entertained the idea of taking me to the doctor.
‘What would they say – “We think our child is a magnet”? Medicine was very different back then and I think if my mother had said that to a doctor she would have been taken away by the men in white coats.
‘When I was a child we constantly had the TV repair man round because I had interfered with the electronics in some way. ‘
‘And they gave up buying me watches because they would just stop.’
It was only earlier this year that Miss Allison discovered that metal objects would stay on her skin when she placed them there.
She says her body can emit a negative or positive charge, depending on the time of the month.
This means she will repel some objects and attract others, and vice versa, depending on the charge.
She added: ‘Metal objects don’t fly towards me, but when I put them close to my skin I can feel a pull. They tend to stay on for longer if they are near a bone – I don’t know why.’
‘They can stay on me for up to 45 minutes without me touching them. Sometimes I feel like a fridge covered with magnets.’
‘My son has grown up with my magnetism so he finds it normal. But he did used to complain when it stopped his battery-operated toys from working.’
Kathy Geminiani, an electrotherapy expert, said it is possible that Miss Allison has a stronger charge in her body.
She said: ‘Everyone has a charge, all slightly different. It sounds like Brenda is highly charged.’
Sandy Lawrence of Electrosensitivity UK said: ‘This condition is affecting more and more people, many of whom have to leave their jobs and can’t even go to the shops.
‘It’s great that this woman’s condition has been highlighted as it is not officially recognised in the UK although it is in other countries.’