With hindsight, it could have been her "one chance to prevent what was about to happen", said Kate McCann, adding: "And I blew it.

London - Kate McCann slept alone the night before Madeleine vanished because her husband had offended her at dinner, it emerged on Sunday.

Upset by Gerry's 'abrupt' behaviour, she took to a spare bed in the children's room at the family's holiday apartment in Portugal.

In her forthcoming book, which was serialised in the Sunday Times, Kate also reveals she is haunted by the belief that Madeleine tried to tell her that somebody had tried to break into the children's bedroom.

With hindsight, it could have been her 'one chance to prevent what was about to happen', said Kate, adding: 'And I blew it.'

Madeleine, who was three, disappeared from her bed in the family's apartment in Praia da Luz on the evening of May 3, 2007, while her parents were eating at a nearby tapas restaurant - as they did every night of the holiday.

The possible missed chance came at breakfast on the day Madeleine vanished, when the little girl disconcerted her mother by asking: 'Why didn't you come when Sean and I cried last night''

Kate, 43, says: 'Not for a moment did we think there might be some sinister explanation. But it is [now] my belief there was somebody either in or trying to get into the children's bedroom that night, and that is what disturbed them.

'So haunted have I been ever since by Madeleine's words that I've continued to blame myself for not sitting down and making completely certain there was no more information I could draw out of her.'

Her emotional book, called Madeleine, is being published this Thursday - the day of Madeleine's eighth birthday.

In one extract, Kate describes her horror at discovering a predatory paedophile could easily have been tipped off that Madeleine was vulnerable, by a staff note on display at reception which revealed the McCanns 'were leaving our young children alone ' and checking on them intermittently'.

The note was written by a receptionist to staff explaining why they wanted to reserve tables every night close to their Algarve apartment.

Although she is 'loath' to make it public by writing it in the book, Kate describes how she and Gerry had a row on the final night before their daughter was lost.

As the couple and their holiday friends were enjoying a drink at the bar, at 11.50pm, Gerry 'abruptly announced' that he was tired and off to bed.

His wife was 'slightly hurt' he had gone without her, and writes: 'He's not a touchy-feely guy. Like many men, he assumes I take his feelings as read and doesn't see any need to express them with soft-soaping, flowers or cards.

'I am not sure why I was miffed by his lack of social graces that evening. Perhaps because the other guys in the group were all attentive 'new men', compared with Gerry at least, and I was a bit embarrassed.'

When she followed him a few minutes later, she found him already asleep and snoring and so, 'still feeling a bit offended', she chose a bed in the children's room because 'my peaceful slumbering babies were more attractive room-mates'.

Kate, whose 384-page book is being serialised in The Sunday Times and The Sun newspapers, says she still feels sad at the memory - though stresses the 'isolated' incident was not reflective of their relationship as a couple.

In an interview with The Sunday Times, Kate said her hospital consultant husband had an ability to 'switch off' from the grief, and was 'functioning' again much sooner than she was.

The former GP admitted: 'Sometimes I found it almost offensive, as if somehow he wasn't grieving enough.'

Recalling a television appeal to the abductor they recorded together, Gerry added: 'That day I remember we were concerned we weren't crying. The thing is, we're not actors. We were trying to focus on getting our message out.'

The McCanns, of Rothley, Leicestershire, are hoping the sale of the book will raise '1 million to fund the continued search for their missing daughter.

On Sunday, Kate and her youngest daughter Amelie attended church in the village, where prayers were said for Madeleine.

Kate dispels suggestions she and Gerry were drunk on the fateful night, saying their alcohol consumption was 'hardly excessive', and that although their group of nine friends was noisier than other tables, they were not 'partying wildly'.

In fact, she said they were so tired they nearly had dinner inside their own apartment the night Madeleine vanished - but then decided that would be anti-social. Kate revealed it took two traumatic bouts of IVF treatment to conceive Madeleine.

After two years of failing to get pregnant, she said she 'didn't think twice' about going down the IVF route, and her first attempt seemed to go well.

She felt so confident and excited, going to the hospital two weeks after the embryos were implanted, that when the pregnancy test was negative, 'I simply couldn't believe it', she recalls.

The couple were keen to start trying again immediately, but a practical problem stood in their way: at the point Gerry would need to provide his sperm, he was due to give a presentation at a cardiac conference in Berlin, an important stepping stone in his career.

He cancelled the trip, the procedure was successful, and at six weeks' pregnant, Kate had a scan and saw a beating heart. - Daily Mail