While anyone calling themselves a radiographer, a dietician, an art therapist or an occupational therapist must be qualified and registered with a regulatory body, anyone with an ultrasound machine can call themselves a sonographer. This has resulted in a proliferation of high-street clinics offering pregnancy scans, with no guarantee that the scan will be conducted by a trained sonographer who knows how to read and interpret it, the SoR says.

Gill Harrison, the SoR's professional officer for ultrasound, says: ‘Patients often don't know who's conducting their scan. Many are appalled when they realise that someone with no qualifications, or who has been struck off a professional register, can still perform their ultrasound scan.'

The SoR is calling for sonographer to become a protected title, which would mean that only those who are properly qualified and registered with the appropriate regulatory body would be allowed to call themselves a sonographer.

In addition, it would mean that only someone who has completed approved postgraduate qualifications in sonography, or a practitioner who has taken an accredited undergraduate degree course in sonography – approved and recognised by the regulator – would be allowed to call themselves a sonographer. This would help expectant parents to understand who was carrying out their scan – and what qualifications they had.

Katie Thompson, SoR president and a hospital sonographer, said: 'When people go for a scan or any kind of diagnostic test, they assume that the person they're going to see is qualified to do it. They don't realise that anybody can buy a machine and call themselves a sonographer.

'With registration, no-one would be able to call themselves a sonographer unless they were on that register. And if there was a problem or a complaint, the patient would be able to refer them to their regulatory body.'