Google is to ban adverts for essay writing services - following claims that plagiarism is threatening the integrity of university degrees.

There have been complaints from universities about students being sold customised essays on the internet.

The advert ban from the Google search engine has been "warmly welcomed" by university authorities.

But it has angered essay writing firms which say this will unfairly punish legitimate businesses.

From next month, Google will no longer take adverts from companies which sell essays and dissertations - and the internet company has written to advertisers to tell them about the policy.