Mystery shrouds the death of a "thoroughly inspirational" fundraiser, after an inquest could not determine what caused his fatally allergic reaction.

Accounts manager Sandro Buttaci, 40, collapsed at his home in Ashridge Way, Morden, on February 4 after attempts to revive him failed.

At Westminster Coroner’s Court on Wednesday, April 4, the coroner’s officer Terry Lovegrove said the former Wimbledon College student had died from an anaphylactic shock.

Anaphylaxis is caused by an extreme and potentially fatal reaction to certain foods, insect stings or drugs and causes the sufferer rapid chemical changes or difficulty in breathing.

Speaking after the inquest Mr Lovegrove confirmed the coroner had ruled Mr Buttaci had died of natural causes, but the exact agent which caused the fatal allergic reaction was unknown.

Mr Lovegrove said Mr Buttaci had eaten a small piece of steak earlier that evening which had caused him to cough and vomit, but had not been the cause of his death.

Last year Mr Buttaci raised nearly £700 for the Royal Marsden Cancer Centre in Sutton who cared for one of his relatives who underwent chemotherapy.

He said he was “indebted” to the hospital and said: "Unfortunately cancer and leukaemia effects more and more people - I never thought that it would affect me so closely - but their efforts are helping more and more people to beat it.”

The Old Wimbledonians released a statement on their website which said he would be "sadly missed".

To leave a tribute to Mr Buttaci call 020 8722 6336; or email: cburnett@london.newsquest.co.uk.