I was watching Harry Potter and the Chamber of Secrets and I would like to know how Harry, Ron, Ginny, Fred, George, Percy, Arthur, and Molly got to King's Cross Station, since the car only fits 5 people max.

1 Answer 1


By using an Undetectable Extension Charm

An advanced spell that was heavily controlled, the Undetectable Extension Charm was used to expand the interior space of an object without changing the external dimensions. The charm could be used on practical objects such as family tents and official cars.

In Chamber of Secrets the Weasley family used the Ford Anglia to travel to Kings Cross which had an Extension Charm placed on it... illegally...

The Ministry of Magic has therefore laid down a strict rule that capacity-enhancement is not for private use, but only for the production of objects (such as school trunks and family tents), which have been individually approved for manufacture by the relevant Ministry Department. Both Mr Weasley and Hermione Granger were acting unlawfully when they enhanced, respectively, the interior space of a Ford Anglia, and a small handbag.

Extension Charms, By J.K. Rowling, Originally published on Pottermore on Aug 10th 2015

The next year in Prisoner of Azkaban the family is loaned a Ministry car due to the safety concerns around Harry which again had the same charm, but legally!

Also seen in use on the Weasley's tent, Hermione's handbag, and Newt's briefcase.

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    Was the Ford Anglia an official ministry car? I would think that if Arthur had illegally enchanted it to fly he would have no qualms about illegally increasing its space. Jan 19 at 16:50
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    it isn't a ministry car
    – Au101
    Jan 19 at 18:47
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    'Yes, Arthur, cars,' said Mrs Weasley, her eyes flashing. 'Imagine a wizard buying a rusty old car and telling his wife all he wanted to do with it was take it apart to see how it worked, while really he was enchanting it to make it fly.'
    – Au101
    Jan 19 at 18:51
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    Mr Weasley blinked. 'Well, dear, I think you'll find that he would be quite within the law to do that, even if, er, he maybe would have done better to, um, tell his wife the truth ... There's a loophole in the law, you'll find ... as long as he wasn't intending to fly the car, the fact that the car could fly wouldn't -' 'Arthur Weasley, you made sure there was a loophole when you wrote that law!' shouted Mrs Weasley. 'Just so you could carry on tinkering with all that Muggle rubbish in your shed! And for your information, Harry arrived this morning in the car you weren't intending to fly!'
    – Au101
    Jan 19 at 18:54
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    But that doesn't necessarily mean the use of the undetectable extension charm was legal, it wasn't, as that was apparently prohibited generally (however that's not in the book series, that's some Pottermore extra stuff). Those quotes were about the misuse of Muggle artefacts. 'It's all to do with bewitching things that are Muggle-made, you know, in case they end up back in a Muggle shop or house.' And yes in PoA they were loaned Ministry cars which were also bigger on the inside and expanded as reqd. due to the apparent threat to Harry's life from Sirius Black
    – Au101
    Jan 19 at 18:58

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