The victim died at Basildon and Thurrock University Hospitals NHS Foundation Trust in Essex.

The patient's family has asked no details of their relative be released.

The trust said in a statement it "would like to extend their deepest sympathies to the family affected as they come to terms with their loss".

The number of people in the UK who are thought to have died after contracting swine flu has doubled in the past three days to 15 - with dozens more critically ill.

The UK now has the third highest number of confirmed cases of the virus in the world after the US and Mexico, where the outbreak began.

Chief Medical Officer Sir Liam Donaldson said London and the West Midlands were approaching epidemic levels.

He said there were 335 people in hospital in England with swine flu, 43 in a critical condition.

However, Sir Liam admitted it was unknown how many people in the UK were suffering from the virus as many would be treating themselves at home.

It is unclear where or when the latest deaths linked to swine flu occurred. Of the 15, 13 were in England.

Justin McCracken, chief executive of the Health Protection Agency (HPC), said the organisation would not be releasing information about individual deaths.

He said it was a local decision in each case whether to release details of where and who the victims were.

Sir Liam said the latest data from 100 GP surgeries around England showed that about 27,000 people per week were being diagnosed as having a flu-like illness.

Of these, an estimated 8,000 will have swine flu.

The latest figures show there are 9,718 confirmed cases of swine flu in the UK - just behind Mexico, with 10,262 cases. The US currently has 33,902 confirmed cases.

Last week Health Secretary Andy Burnham said 100,000 new cases of swine flu could occur in the UK by the end of August.

It is expected to surge in the winter months when flu is more prevalent.

Figures show youngsters aged five to 14 are being particularly badly affected by swine flu, followed by one to four year olds.

Worldwide, there have been 94,512 cases of swine flu in 135 countries, with 429 deaths.