Could Tian Tian give birth to a cub tomorrow? Picture: AP

Scottish Government officials and staff at Edinburgh Zoo discussed in late July that Tian Tian was definitely pregnant and that her expected date, at the time, was August 25.

A spokesperson for Edinburgh Zoo said: “Giant panda breeding is a very complicated process but we believe that Tian Tian is pregnant.

“Although a specific date was suggested, like all babies, it’s hard to predict precisely and the panda breeding season can last until late September.

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Tian Tian and Yang Guang arrived at Edinburgh Zoo in December 2011. Picture: Ian Rutherford

“Tian Tian is being closely monitored by our expert team and we will be the first to share any news as soon as we can.”

If the pregnancy has progressed as expected since the exchange of emails, the birth of the UK’s first panda cub is imminent.

The remarkable turn of events, following several years of failed pregnancy attempts, has been revealed in partially redacted emails released under the Freedom of Information Act.

Tian Tian and Yang Guang arrived at Edinburgh Zoo in December 2011. Picture: Ian Rutherford

Tian Tian, who arrived in Scotland as part of breeding pair with Yang Guang in 2011, was artificially inseminated for the fifth time late last year.

The decision to go ahead with artificial insemination came after the zoo decided there was now no prospect of Tian Tian and Yang Guang ever mating naturally.

Dcuments released today show that in late July this year Tian Tian’s pregnancy was ‘on track’ and the mother-to-be is ‘doing real well’.

An email, dated July 25 2017, from Iain Valentine, director of giant pandas at the Royal Zoological Society of Scotland (RZSS), to the Scottish Government, stated: “TT doing real well. As things are at the moment, she seems on track but I have shifted possible birth date to around 25th August. Will be able to be a bit more precise in a week’s time.

“So she is about 30 days out now and pregnancy proper has now begun in what we think is a 37 day pregnancy. See or hear from you soon. My best, Iain.”

The email that prompted the revelation was sent earlier that day from the Scottish Government reading: “I was reminded that this is the season when we might be expecting some baby pandas and I know [Scottish Government Official] has been in touch with you about the progress there.”

A previous email from Iain Valentine, dated July 10, 2017 read: “All seems fine with TT at the moment... waiting on results from last set of samples so will see what they turn up.”

An email from a Scottish Government official, dated July 4, revealed how excited they were over the zoos potential new resident, stating: “Thanks for the update - exciting times (we hope).”

An earlier email from Mr Valentine, dated June 29 2017, read: “Tian Tian is doing just fine and latest sample results are showing that things are on track at the moment.

“It’s a bit early to give a potential birth date if there is to be a birth, a good window of opportunity to look to is from the end of July to mid August.

“I will be able to home in on a potential date a bit better in about ten or so days time when another set of tests kick in. Will keep you posted on TT as things move forward.”

The two giant pandas arrived in Scotland in December 2011 and are rented by Edinburgh Zoo from the Chinese government for ten years, costing an annual fee of around £600,000.

Panda experts at Edinburgh Zoo carried out the artificial insemination late last year after hormone monitoring revealed that Tian Tian hit peak oestrus levels.

It was the fifth time Tian Tian has been artificially inseminated and the move sparked renewed criticism from animal rights campaigners, who accused the zoo of being more focused on making money than the panda’s welfare.