Spanish police are investigating whether Cilla Black's death was caused by a fall from a dizzy spell, caused by a sudden temperature change in the room.

Black may have walked from an air-conditioned room in to midday heat, with the change in temperature causing her to become dizzy, the Sun newspaper reported.

A post-mortem examination is due to be carried out today, to determine the cause of death, but police in Spain have said "everything at this stage is pointing towards her death being the result of natural causes".

Her sudden death at her home in the south of Spain has left friends, family and the British public in shock.

The Herald:

Holly Willoughby tweeted this picture taken with Cilla following news of her death

Tributes have been pouring in for Black, 72, led by close friends such as Sir Cliff Richard, Sir Paul McCartney and Christopher Biggins.

She rose to fame in the 1960s as an associate of The Beatles and their manager Brian Epstein.

Born Priscilla Maria Veronica White in Liverpool, she became the first woman to have her own prime-time chat show on BBC1.

Her star continued to shine brightly, and she had two number ones in 1964 - Anyone Who Had A Heart and You're My World.

In a touching tribute to her, Sir Cliff Richard said he was due to visit her at her house in Spain next week.

The Herald:

Cilla Black with Joe Loss, Lionel Blair and Billy in 1965

"Her passing away is a particular shock because despite the aches and pains we all suffer, she was always so upbeat," he wrote in the Sun.

Former Beatle Sir Paul McCartney paid tribute to her from Los Angeles, saying: "Such a shock to hear about Cilla's passing. She was a lovely girl who infected everyone with her great spirit.

"From first meeting her as a cloakroom girl at the Cavern in Liverpool, to seeing her many times since, she always had a fun-loving dignity that made her a great pleasure to be around.

"She had a fine distinctive voice and was always a bit of a laugh. It was a privilege to know and love her."

And former Beatles drummer Ringo Starr said: "I just heard the news Cilla Black has left us. She was a good friend, we will all miss her. Peace to Cilla, peace and love to the family, R&B."

EastEnders star and her good friend, Barbara Windsor, described her death as "awful".

She told the BBC: "I was only with her a couple of weeks ago. I've seen her twice in the last few weeks, and as always she looked immaculate. That was the thing about Cilla, she always looked spot-on. But I knew she wasn't very well, she didn't seem well."

Windsor added: "I liked her, we got on well. She was nothing like me in personality at all, but she was a good, good all-round performer."

The Herald:

Cilla in 1963

Cilla Black was born Priscilla Maria Veronica White on May 27, 1943 and was encouraged to sing by her family. In the early 1960s she got a part-time job as a cloakroom attendant at the famous Cavern Club in Liverpool where the Beatles regularly played.

She quickly impressed the Beatles and others with her talent, when she gave impromptu performances at the Cavern. At this time, she also worked as a waitress in the Zodiac coffee lounge, where she met her future husband and manager Bobby Willis.

Cilla was introduced to Brian Epstein by John Lennon who persuaded him to audition her. In September, 1963, Epstein signed her up as his only female client.

The Herald:

Cilla with Brian Epstein, Tommy Quickly and Billy J Kramer in 1964

Her debut single, Love of the Loved, written for her by Lennon and McCartney, was a relative failure. But her second single the Burt Bacharach-Hal David composition, Anyone Who Had A Heart shot to Number One and became the biggest-selling single by a female artist in the history of British popular music.

This launched her on an extraordinary pop career, with 20 consecutive Top 40 hits on the British single and EP charts, including 11 British Top Ten singles and two consecutive Number One singles in 1964.

Her hits included You're My World, Alfie, the theme song from the Michael Caine film of that name, and Step Inside Love.

The Herald:

Cilla with Petula Clark and Sandie Shaw at the Dorchester Holel, London in 1965

Cilla's pop career persisted until the end of the 1960s, by which time she was an internationally-acclaimed star, having notably successfully broken into the notoriously difficult United States market.

She branched into acting with 1964's Ferry Across the Mersey, which featured Gerry & The Pacemakers, also out of Epstein's stable.

But by August 1967, only days before his premature death, Epstein had engineered Cilla's switch to television. It was a shrewd move and, largely through her own sheer drive, she remained at the height of popularity until the end of the century and beyond.

The Herald:

Cilla was awarded and OBE in 1997

Her own variety show for the BBC regularly commanded staggering audiences of 22 million. So while her pop career was declining she was developing into the most popular figure on television.

It was this resounding TV success which was eclipsing her musical career, although she always said she preferred to be remembered for her songs than for anything else.

Blind Date (1985-2003), Surprise! Surprise! (1984-1999) and Moment of Truth (1998-2001) never lost their popularity during their long and successful runs.

Cilla was awarded an OBE in 1997. In 2005, her autobiography What's It All About? became a best-seller. She has been the recipient of many TV honours and awards.

The Herald:

Cilla with her husband Bobby Willis in 1997

Willis, her husband and manager, to whom she was married for over 30 years, died in the late 1990s.

Cilla is survived by three sons, one of whom, Robert, succeeded his father as her manager.