The crash in oil prices is having a curious effect on everyday economics: oil is now cheaper than bottled water.

Brent crude was trading just below $60 a barrel on Tuesday morning, meaning that it now costs about 24 pence a litre. An oil barrel is 159 litres and currently the British Pound is 64 pence to the dollar.

As Reuters' John Kemp tweeted this morning, that is about 40% cheaper than a bottle of Evian mineral water in British supermarkets, where a six-pack of 1.5 litre bottles sells for £3.80.

Brent is still more expensive than Tesco brand Ashbeck sparkling water, which is 20 pence a litre if you buy the 4-pack of 2 litre bottles from the Tesco online store.

To hit that price, oil would have to go as low as $42.61 a barrel.