Domestic gas boiler engineers are not carrying out basic checks and are suggesting expensive, unnecessary repairs, according to Which?.
In response to the claims, HomeServe said: "We employ a robust checking process, including technical audits, and qualifications and good repute checks. Once a contractor works for us we manage their performance closely and have a thorough complaints procedure. Yearly audits ensure high technical and customer service standards."
British Gas said: "We work hard to give our customers the best possible service. Our engineers fix 95% of boilers on their first visit. We offer a 24-hour emergency service, and our engineers are available as late as 8pm, seven days a week."