About 20,000 abortions a year are performed after 12 weeks - 10 per cent of the total. And among those statistics is the 16-year-old who is about to undergo the procedure.
Like many in her situation, she has looked on the internet to find out exactly what the operation involves. "It doesn't look very nice, but it's what has to be done," she says, "so I'm not really that bothered about it."
If she'd asked the surgeon, scrubbing up in the operating theatre, he would have given her his standard, brief answer: "The terminology I'd use would be that the foetus is removed and that the foetus dies as a result of that process," says Dr John Spencer, who is the senior clinical director for Marie Stopes and one of only a handful of doctors in the country who perform abortions right up to the legal limit of 24 weeks.
"Women hardly ever ask for any more details."
But in the Dispatches programme, Dr Spencer will break a huge medical taboo and spell out exactly what happens. Though we do not show the aborted foetus, what viewers will see and hear may very well shock them, but it is a vital contribution to the whole debate.
In the first 12 weeks or so of pregnancy, doctors can use a simple suction procedure. After that, the surgery becomes more complicated.
Dr Spencer opens a fresh pack of shiny instruments. He's an extremely calm, softly spoken man, which somehow makes his words all the more devastating. "The foetus can't come out in one go. We haven't dilated sufficiently for that. The foetal parts are soft enough to break apart as they are being removed..."
In other words, he has to dismember the foetus inside the uterus and pull it out, bit by bit. He uses an ultrasound scan to guide him. Even then, some body parts are too large to come out intact.
To illustrate what happens, Dr Spencer grips his thumb between the surgical forceps and squeezes gently. "Those parts are the skull and then the spine and pelvis, and in fact they are crushed..."
The operation on the 16-year-old is over in 12 minutes. The bowl with what they call "the products of conception" is quickly wheeled out of the theatre, covered in yellow plastic.
The surgical procedure is done under general anaesthetic. A couple of hours later the slightly groggy teenager is driven home by her mother, on her way to getting on with the rest of her life.
