The Duke of Edinburgh has spent the past two nights in hospital with a chest infection after picking up a cold earlier in the week.

He was admitted to King Edward VII Hospital in Central London on Thursday afternoon for “assessment and treatment”, but is understood to be working from his bed and replying to correspondence.

A Buckingham Palace spokeswoman said that the Duke, 86, had cancelled his attendance at a dinner in aid of Macmillan Cancer Support in Windsor last night but engagements next week remain in place. There has been no change to plans for him to accompany the Queen on a state visit to Turkey next month.

The Duke is renowned for his robust health despite his advanced years, but pulled out of a commitment to attend a thanksgiving service on Wednesday for Sir Edmund Hillary, the first person to reach the summit of Everest, because he had been taken ill with a cold. He joined the Queen to formally say goodbye to Nicolas Sarkozy, the French President, and his wife last week after their state visit.

The Duke walked into the hospital and is being treated by Professor John Cunningham, whose speciality is general medicine and who is based in Harley Street. King Edward VII is a private clinic that regularly hosts members of the Royal Family. The Duchess of Cornwall had a hysterectomy there in March last year and the Queen was a patient in 2003, when she had noncancerous growths removed from her face and an operation on her knee.

The Duke’s illness comes at the end of a week in which the coroner at the inquest into the death of Diana, Princess of Wales, ruled that there was not a shred of evidence to support years of conspiracy theories aimed at the Duke.

King Edward VII’s Hospital for Officers, established in 1899, has 61 private en-suite air-conditioned rooms costing £500 a night. The Duke is rarely ill and most of his ailments over the years have been sport-related. Rumours of a 15-year history of heart problems, reported in October, remain unconfirmed. He gave a robust denial to other rumours of ill-health after he decided not to take part in the Trooping the Colour ceremony on horseback at the age of 82.

He memorably shouted at an estate worker in Sandringham: “Do I bloody look ill?”

Recent injuries include a black eye in 2005, sustained when he slipped in a bath and caught the side of his eye with a thumb. He pulled out of an engagement in May 2006 when he had a trapped nerve in his neck. He has had surgery three times; to remove a cyst from his right wrist in 1967, to repair a hernia in 1987, and to erase a small benign growth in his nose in 1996.

On Monday the Duke is due to attend two engagements at Windsor Castle, a council meeting and a dinner to mark the 60th anniversary of the establishment of the State of Israel.

The Duke’s most persistent affliction has been arthritis in his right wrist, caused by playing polo and exacerbated by thousands of handshakes. He gave up polo in 1971, the year of his 50th birthday, and has had to change his greeting style from a firm-gripped handshake.

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