ITV News understands that one of Britain's richest men is being questioned by police in connection with his wife's death in Chelsea.
Hans Kristian Rausing, the heir to the Tetra Pak drinks carton empire, was arrested yesterday on suspicion of alleged drugs offences. Police then discovered the body of his wife Eva at their home in Cadogan Place.
It's understood that he was then further arrested in connection with her death and that he is now receiving medical treatment.
Police are treating the death of Mrs Rausing as "unexplained" and a post-mortem examination held yesterday failed to establish a formal cause of death. Investigators said they are awaiting the results of further tests.
Relatives of the couple, whose past drug problems have been widely reported, last night revealed their sorrow over the death.
A statement from the family of Mrs Rausing, whose maiden name was Kemeny, said: "Tom and Nancy Kemeny along with all of their family are deeply saddened by the death of their beloved daughter, Eva Louise Rausing.
"Eva was a devoted wife for 20 years and mother of four much-loved and wonderful children.
"During her short lifetime she made a huge philanthropic impact, supporting a large number of charitable causes, not only financially, but using her own personal experiences.
"She bravely fought her health issues for many years. The family is devastated at her death and asks to be given privacy at this difficult time."
The Rausing family said they were "deeply shocked and saddened to hear of the tragic death of their daughter-in-law" and also asked for their privacy to be respected.
Mr Rausing stands to inherit the £5.4 billion business enterprise built by his Swedish father.