A powerful Greek family have accused the NHS of letting an heiress die on their watch after she was bitten by an insect, the Daily Mail can reveal.

Marissa Laimou, 30, was tragically found dead in her bed by a housekeeper at the townhouse she lived in with her parents in upmarket Knightsbridge, central London, on September 11.

In a heartbreaking twist, Ms Laimou - also known as Lemos - had overcome breast cancer and an extremely rare blood disease in the months before she died.

In the days before her death, her family say she voiced major concerns for her health at two well-respected London hospitals - including one she was rushed to in an ambulance - but doctors ultimately decided to discharge her.

The wealthy Lemos family, one of the biggest dynasties in the Greek shipping industry, are now planning to take legal action, a relative confirmed to the Mail, adding: 'They are going to go against them of course. This is 100 per cent negligence. Marissa is gone because of them.