At the same time, Labour leader Jeremy Corbyn had been written off as unelectable with only support coming from he hard left Momentum movement which was filling the ranks of his party.
What happened next is well documented.
However, it has now been claimed that Mrs May could not have romped home on June 8 even if the ill-fated manifesto and ditched care-funding plan had not been the key turning point of the election campaign.
A top astrologer has claimed nothing could have helped Mrs May regardless of what happened during the campaign, and that Mr Corbyn was bound to gain on her.
Astrologer Helen Sewell, who writes for journals and websites, has compiled astrological charts for Mrs May and Mr Corbyn, and other world leaders, including Donald Trump and Hillary Clinton.
She claims the Tory and Labour leaders’ fates were sealed by the stars and planetary alignments.
She revealed her findings at the 27th annual Glastonbury Symposium, an annual conference dedicated to the paranormal, conspiracy theories, alternative thought, and new age philosophies.
Astrology is the belief that the movements and relative positions of celestial bodies has an influence on the individual lives of humans and the natural world as a whole.
Astrologers claim to be able to predict future events through upcoming changes to the positions of stars and planets.
In a lecture called The Astrology of Current Events Mrs Sewell revealed why Mrs May lost seats and Mr Corbyn gained momentum.
Mrs Sewell produced a horoscope chart for Theresa May which showed “she should never have called the election” at that time, because of the alignments of various celestial bodies.
She said: “She definitely should have seen an astrologer because if you have Neptune, the planet is to do with escapism and you will not really be grounded.
“If it goes over your Mars you will lose energy – your power – you will feel very ineffectual and often quite ill actually.
“So she definitely should not have run the election with that kind of transit going on.”
Mr Corbyn, however, was given a boost of good luck by the astrology at the time.
She said: “Jeremy Corbyn is another air sign – Gemini.”
She said that the emergence of Mercury at the time had made him “particularly good” at public speaking.
The astrologer said: “This was very fortunate for him and he had Venus square to Jupiter which is very fortuitous.”
However, Mrs Sewell did bring Mrs May’s infamous footwear into the horoscope.
She said: “Theresa May has Venus in Leo, and might have the moon in Leo as well.
“Have you ever noticed her kitten heels and leopard skin thing. I think that is Leo coming out in her.”