A personal diary written in 1969 by the wife of "the Fifth Beatle" has been uncovered shedding new light on the Fab Four's break up a year before it happened. 

Joan Taylor kept the entries while married to Derek Taylor, who was The Beatles press officer and close friend at the height of their stardom. 

It provides a fascinating insight into the personal relationships and business-life of the legendary Liverpudlian band during the fraught period of early 1969.

The diary also gives a unique first-hand look at the events leading up to the break-up of The Beatles and their Apple Records business as the cracks began to show.

Derek was close with George Harrison but less so with Paul McCartney which is revealed in Joan detailing a "rotten day with Paul" and "More trouble with Paul Mc."

One entry even reveals the moment George Harrison quit the band - "George has walked out of The Beatles and won't go back."

The diary also includes day-to day details of Joan’s life such as taking delivery of John's piano and having 'good nights out' with him and Yoko in happier times. 

Joan wrote: "We came home with John, Yoko and Pete and played records and smoked.

"John and Yoko are buying a house in Virginia Water."

But later entries describe Derek coming home from work exhausted and having sleepless nights, which spelled "the beginning of the end."

One extract reads: "More trouble with Paul Mc, it went on most of the day and night.

"Pattie bought Derek home after visiting George in hospital. 

"We are both pretty exhausted by it all. I think this is the beginning of the end for Derek at Apple."

Another says: "Derek is having a particularly difficult time at the office as a result of John's interview on disc.

"We had a bit of bother on the phone. George came for a chat and when they came home it was all OK but they looked wacked."

A further extract reads: "He has had a rotten day with Paul and another sleepless night."

Another details the arrest of George and Pattie Harrison when police carried out a drugs bust at their home on March 12, 1969 - the day of Paul McCartney’s wedding.

It reads: "George and Pattie were busted this afternoon. Derek went with George to the police station." 

The diary is now expected to fetch between £400-£600 when it goes under the hammer at at Special Auction Services in Newbury, Berks., on March 26.

Derek Taylor became The Beatles' press officer at the height of Beatlemania, accompanying them on their first tour of the USA.

He worked as head of communications when they first set up Apple Corps in 1968 ahead of the band officially splitting in April 1970.

Derek, one of several associates to earn the moniker "the Fifth Beatle", confirmed the Beatles break-up after Paul hinted in a press release the group was no more.