'Mummy, I've had the best day ever' said Madeleine just before she was snatched

In her first interview without husband Gerry at her side, Kate McCann said the four-year-old had spent an activity-packed day at the Kids' Club run at the family-friendly Mark Warner complex in Praia da Luz, Portugal.

One of the last things Madeleine talked to her mother about before she was abducted from her bed was her exciting day.

Mrs McCann said: "On the evening she went missing, before she went to bed she said, 'Mummy, I've had the best day ever. I'm having lots of fun'."

She described the family's last day together as police began another search at the home of Robert Murat, the only suspect.

Recalling the enjoyment of Madeleine and her twin siblings Sean and Amelie, two, Mrs McCann, 39, added: "The kids had a fantastic time. We all did but it was lovely seeing them having fun.

"We did use the Kids' Club and very often did activities there. Madeleine in particular had a ball. They did swimming, went on a little boat, went to the beach, did lots of colouring in and face painting.

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"Madeleine is at the age where she could really enjoy it. They played tennis which she loved, she was so happy. They had a little dance prepared for Friday. It was a little preparation they were working on in the days before."

Asked about the dance, Mrs McCann's voice dropped to a whisper as she added: "I don't know what it was, I never got to see it."

Two UK detectives accompanied by ten Portuguese police officers yesterday arrived at the home of 33-year-old Murat at 7am. The house, where Murat lives with his elderly mother, is about 100 yards from the holiday apartment from where Madeleine was taken three months ago. Officers used hedge-trimmers and rakes to clear the heavy vegetation.

Expat Murat was not arrested but has been told that the search could take up to four days and that it will have three phases – clearing the vegetation, scanning the grounds to detect buried items or recently disturbed earth and, if necessary, digging.

The development follows a possible sighting of Madeleine in Belgium last week. DNA tests are being carried out on a milkshake bottle that a girl fitting her description was drinking from at a cafe. Results are due this week.

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As she continues her vigil in Portugal waiting for news of her daughter, Mrs McCann also tearfully told how she was stricken with "panic, fear and guilt" after discovering Madeleine missing when she and Gerry returned from having dinner with friends.

Mrs McCann said: "There was about 20 seconds of disbelief where I thought 'That can't be right'. I was checking for her. Then there was panic and fear.

"I was screaming her name. I ran to the group. Everyone was the same. It was just total fear. I never for one second thought that she'd walked out. I knew someone had been in the apartment because of the way it had been left.

"But I knew she wouldn't do that anyway. There wasn't a shadow of doubt in my mind she'd been taken. That's why the fear set in.

"Then you go through the guilt phase. Straight away, because we didn't know what had happened. We were just so desperately sorry. Every hour now I still question 'Why did I think it was safe?'

"I do feel regret. I've gone through all my life and said I never want to have any regrets, but you can't not regret something like that. I feel desperately sorry to her that we weren't there."

Mrs McCann also described the joy she had experienced at her IVF birth after five years of trying unsuccessfully for a baby.

She said: "There came a point when we admitted we needed help. I was so desperate to have a child I'd try anything.

"I know that IVF isn't everyone's choice but I wanted to try it. We had one unsuccessful attempt before Madeleine.

"When I got pregnant with Madeleine it was just fantastic."

Twins Sean and Amelie were born 20 months later, also after IVF treatment. They talk about Madeleine all the time, she said. "There are photographs of her all around."

• Almost one in ten parents have scrapped plans for foreign holidays this year as a direct result of Madeleine's abduction, according to a survey by market research company OnePoll.