Men who do not openly express their anger if they are unfairly treated at work double their risk of a heart attack, Swedish research suggests.

The researchers looked at 2,755 male employees in Stockholm who had not had a heart attack when the study began.

They were asked about how they coped with conflict at work, either with superiors or colleagues.

The researchers say their study shows a strong relationship between pent-up anger and heart disease.

Writing in the Journal of Epidemiology and Community Health, the researchers called the various strategies for keeping things bottled up, covert coping.

A £20million, decade-long investigation overseen by the World Health Organisation (WHO) will publish evidence that heavy users face a higher risk of developing brain tumours later in life, The Daily Telegraph can disclose.

The conclusion, while not definitive, will undermine assurances from the government that the devices are safe and is expected to put ministers under pressure to issue stronger guidance.

A preliminary breakdown of the results found a “significantly increased risk” of some brain tumours “related to use of mobile phones for a period of 10 years or more” in some studies.

The head of the Interphone investigation said that the report would include a “public health message”.

Britain’s Department of Health has not updated its guidance for more than four years. It says that “the current balance of evidence does not show health problems caused by using mobile phones”, and suggests only that children be “discouraged” from making “non-essential” calls while adults should “keep calls short”.