Figures obtained by ITV Anglia show hundreds of gas appliances have been worked on by unregistered engineers here in the East of England.
Nearly 250 jobs were carried out by unqualified engineers over the past two and a half years.
Nearly one in five of those were so dangerous the appliances had to be disconnected immediately.
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Leading micro-surgeons from around the world are at a two day conference in Norwich discussing pioneering techniques
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Researchers believe the new technique could help improve the chances of IVF, of which only around one in four attempts are successful.