They seemed primed for panda passion: he was eager to participate in a very rare romantic assignation with a member of the opposite sex, while she was grumpy and off her food. But, as the world waited, nothing happened.

Today all hope finally evaporated that Tian Tian and Yang Guang, the resident Chinese giant pandas at Edinburgh Zoo, would mate naturally.

Despite displaying some encouraging signs the couple, who were unromantically thrust together after prolonged negotiations between the Chinese and UK governments, failed to reproduce and their handlers were forced to give nature a helping hand. After seven days of frustrated updates about their reproductive urges, the zoo confirmed it had performed an artificial insemination on Tian Tian in the early hours of this morning.

She had spent most of the week snubbing Yang Guang’s amorous advances as he ventured down an “indoor love tunnel” to meet her in her quarters. They were together three times a day for 15 to 30 minute intervals – thought to mimic how pandas reproduce in the wild by “mating then separating”.

Iain Valentine, the appropriately-named director of giant pandas at the zoo, admitted at the time Tian Tian was “not quite ready” to breed – but Yang Guang was “more than ready and is a completely different animal”. By the weekend, Tian Tian was displaying the “correct behaviours” for breeding as she had become “very grumpy, went off her food and became a little temperamental”. But despite all of the positive behaviour, the zoo said Tian Tian had displayed signs she would “not be conductive to mating”.

Mr Valentine said the insemination was carried out by two teams working with both pandas. “The timing of the procedure is critical. As soon as Tian Tian hits peak her hormones will start to fall,” he said. There is just a 36-hour annual breeding window for female giant pandas. Any pregnancy will be confirmed in July with cubs born in August or September.

The pair, who have increased visitor numbers at the zoo by 50 per cent, will now be “off show” until tomorrow. The giant panda is the rarest bear on Earth with just 1,600 left in the wild. The zoo pays an annual fee of £600,000 to the Chinese authorities to keep them for 10 years.

Twitter users reacted to the news the pandas were “not up to a Highland fling” by branding the species “evolutionary failures” and claimed keeping them was a waste of money. “All that build up, and then one of the pandas gets a headache… Don’t worry, big guy, we’ve all been there,” wrote one user.

The unhappy couple

Name: Yang Guang

Sex: Yes please.

Age: Nine:

Habits: The zoo says the “gentle giant” likes listening to Smooth FM. He is more sensitive to noise than other giant pandas and has upped his consumption of bamboo to increase his body size to reach “peak physical shape” for the mating season. Courtship includes performing headstands. Not interested in football.

Name: Tian Tian

Sex: No Thanks

Age: Nine

Habits: Already has two children from a previous relationship. Is said to be “quite reserved” and eats her meals – she particularly enjoys cakes and carrots – in a slow and ladylike manner. She is described as “very smart” with a great character. She likes playing football.