The "world's best teacher" says that a culture of excessive testing can damage standards and "decimate morale" among teachers.

Nancie Atwell, a US teacher who won the Global Teacher Prize earlier this year, was visiting a school in London.

She also said that teachers could get more attention from pupils from talking quietly than shouting.

Ms Atwell won a million-dollar prize - but immediately gave the money to her school in Maine.

On her visit to Capital City Academy in Willesden, north-west London, she said part of the prize had been spent on fixing the school boilers.

This extract is taken from the BBC website:

http://www.bbc.co.uk/news/education-34769430