LONDON -- Horses have a funny habit of turning up in strange places.

There was that time a man cantered into Tesco on one in Ireland a few months back, and that memorable occasion when a horse was photographed on a tram.

Still, it's not often the four-legged beasts attempt to board double-decker buses in the UK's capital.

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The horse was photographed by politician Simon Crowcroft on Tuesday afternoon on a road in London -- but what the sweet hell is it actually doing?

Luckily, an official TfL Bus Alerts Twitter account was on hand to offer an explanation.

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We're guessing the trusty steed poked its head through the door to see what was going on after the officer riding it dismounted to board the bus.

Shortly after, the Twitter account for the London Metropolitan Police's Mounted Branch confirmed the story.

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They went on to add that the person who collapsed was taken to hospital "as a precaution", but was otherwise OK.

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Finally -- because all unexpected horse moments need to be made the most of -- here's the sturdy nag from a different angle.

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Good work, horse.