Having come under fire from disappointed after cancelling her last two Wembley Stadium gigs at the weekend, ‘Skyfall’ singer Adele has now incurred the wrath of Sam Smith’s vocal coach, Anthony Wade.

The vocal coach has blasted the megastar for her “slapdash attitude” to taking care of her voice.

"She's got an easy going attitude which people love, but you can't do that with your artistry," the singing teacher told The Sun [via The Express]. "She has an artistic responsibility for the lovely people who have bought her tickets, and she did not take responsibility of her vocals. This is evident."

He added sternly: ”I believe she's had a slapdash attitude about the way she warms up or uses her voice, or she's not being given the correct advice.”

As previously reported on Gigwise, Adele issued an apologetic statement where she revealed her struggles with her voice at the two concerts that did actually go ahead.

She said: "I had to push a lot harder than I normally do. I felt like I constantly had to clear my throat, especially last night. I went to see my throat doctor this evening because my voice didn't open up at all today and it turns out I have damaged my vocal cords.”

It was also claimed that the two cancelled gigs may cost Adele millions of pounds in lost revenue from DVD sales. The gigs were scheduled to be filmed and director Matt Askem had brought in around 100 cameras.

The cancelled dates would have been the climax of her massive month world tour. It is unknown if the dates will be re-scheduled.