Dental nurse 'poisoned boss's coffee with mercury after she was disciplined for leaving a patient alone in dentist's chair while she went to lunch'

Dental nurse Ravinder Kaur, 34, is facing charges relating to accusations that she poisoned two colleagues with mercury while working at a dental practice in Bedfordshire

A bitter dental nurse poisoned her boss's coffee with mercury after being disciplined, a court heard today.
Ravinder Kaur, 34, laced the drink with the metal used to make fillings in an act of 'spite and revenge', it is alleged.
Practice manager Laura Knowles had to be rushed to hospital with stomach cramps after downing the hot drink.
She first thought Kaur might have spat in her cup but noticed a strange tint as she poured the remains down the sink.
Kaur had twice been warned by bosses at the Shams Moopen Dental Practice, Shefford, Bedfordshire, before the incident, Blackfriars Crown Court was told.
'This defendant put mercury amalgam into a cup of coffee she had made for her boss, Laura Knowles,' said prosecutor Samantha Cohen.
'Ms Kaur did so out of spite and revenge because she believed she had been treated unfairly at work by Ms Knowles.
'Ms Knowles drank some of the coffee and she ingested a small amount of mercury.'
She denied administering a poisonous or noxious substance with intent to cause harm.
The court heard that three days before the incident, Kaur had been given a final written warning for leaving a patient in a dental chair while she took her lunch break, the court was told.
She was also questioned over reporting a dentist at the practice to the Care Quality Commission for breaching patient confidentiality before bosses had a chance to investigate.
Jurors were told she offered to make a coffee for Ms Knowles when she arrived at work on March 16 last year.
Ms Cohen said: 'She returned about 15 minutes later with the coffee which she gave to Ms Knowles, and apologised for how long she had taken, saying she had to change the water in the kettle.
'Ms Knowles drank a little bit of the coffee, but it didn't taste right.
'Her first thought was that Ms Kaur might have spat in it, baring in mind three days earlier she had issued a final written warning.
'She took it and started to pour it away, and as she did so she saw grey sludge in the bottom and realised it looked like mercury.

'She started to feel sick and feel stomach cramps. She went to hospital and an X-ray was taken.'
The X-ray revealed small pieces of mercury in her stomach and Kaur was arrested on suspicion of poisoning later that day.
When the cup was analysed it revealed traces of the tin, copper, silver and mercury substance used to make fillings.

Ravinder Kaur, left, is accused of poisoning practice manager Laura Knowles, seen leaving Blackfriars Crown Court after giving evidence today

Accused: Ravinder Kaur, 34, appeared at Blackfriars Crown Court (pictured)

Kaur was trained in using the metal, and knew of the potentially deadly effects of mercury if inhaled, the court heard.
The metal is not as dangerous when swallowed, but can cause stomach cramps.
Assistant dental nurse Kaur had worked at the practice since November 2011, and was described as 'inflexible and not what would be regarded as a good team player' by her boss.
She was suspended from work after the incident but claims someone else may have spiked the coffee to frame her after she made the CQC referral.
Ms Knowles said she was left with stomach cramps that felt like 'early labour pain' after swallowing an oyster-like 'globule' of mercury in the coffee.
She had just returned to work after mourning the death of her father three days earlier. Kaur offered to make her a coffee when she arrived at the surgery.
'She was very kind, offered her condolences for my time off and offered us both, myself and Danielle, a drink,' Ms Knowles said.
It took her 15 minutes to prepare the drink, which Ms Knowles was halfway through before noticing a strange lump.
'I swallowed a texture, I thought that it had been spat in, because of the nature, there was a slimey lump in it, like an oyster. It felt like a globule,' she said.
She poured the drink down the sink, and saw remnants of the substance she immediately identified as mercury.
'Mercury moves very differently to other liquids, you could see it was a very different object that was in there,' she said.
After immediately seeking an appointment at a doctor's surgery nearby, she was told to go to hospital for further checks.
'Within an hour I had stomach cramps and nausea,' she said. 'Like very severe period pains, or early labour pains.'
Following her discharge from Pinehill Hospital in Hitchin, she sat in while practice owner Dr Shams Moopin interviewed Kaur before urging him to call police.
Ms Knowles left the practice in December last year.
The trial continues.

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