The Aries Ingress of March 20, 2017 in London had Moon-ruled Cancer rising and no planets in the first house. Cancer is also the sign of the next angle after the Sun, so Morinus would consider the Moon the Lady of the Year. Here is the chart with Whole Sign houses.
With the Moon ruling the year 2017 in the UK, we expect some type of difficulty to arise fairly quickly after the Ingress because the Moon is applying to conjoin Saturn in the unfortunate 6th house. The Moon and Saturn are only 04 minutes of arc apart, and the 6th house is traditionally a place of open enemies who might attack whoever is represented by the 1st house.
After her conjunction with Saturn in the 6th, the Moon proceeds by transit through the 7th where she will conjoin Pluto in Capricorn in the 7th of open enemies (modern meaning), again suggesting some kind of attack by a Plutonian adversary. Pluto is, of course, disposed by Saturn in the 6th. During her passage through the 7th of open enemies, the Moon will square the cluster of planets in the 10th house of the government and authority figures.
The attack by automobile began on Westminster Bridge in London on Wednesday March 22, 2017 at 2:40 pm. According to news reports, “five people died, including the attacker, and at least 50 people were injured in a terror attack near the Houses of Parliament on 22 March.”
Here is the chart for the first moment of the attack superimposed on the Aries Ingress for London of March 20th.
As you can see, the transiting Moon at the time of the attack lies in the 7th house and is in close square with Uranus (both Ingress Uranus and transiting Uranus) in the 10th. In fact, the Moon is making its final square to the group of planets in the 10th.
Prior to squaring Uranus in Aries in the 10th (sudden aggressive action directed toward government), the Moon had conjoined Pluto in Capricorn in the 7th of open enemies. This is rather perfect symbolism for a terrorist attack against the powers that be.
The transiting Angles often indicate timing. Here the transiting MC is almost exactly sextile Neptune in the 9th of foreign countries, and the transiting ASC is trine Uranus in Aries in the 10th.