The largest hurricane in history has started to buffet the coast of Mexico, with the storm expected to bring torrential rain and winds of up to 200mph.

Thousands of locals and tourists have been evacuated inland or moved to emergency shelters as experts warn Hurricane Patricia could be powerful enough to fling cars down the street.

Waves of 40ft (12m) are also predicted to lash the coastline.

The US National Hurricane Center says it is the strongest storm ever recorded in the Western Hemisphere and the third-strongest ever.

People on the country's west coast are being warned of "catastrophic consequences".

Some 400,000 people are in the eye of the storm but there are not enough shelters for everyone to take refuge.

The storm is expected to is stronger than Typhoon Haiyan which killed 6,000 people in the Philippines two years ago.

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Tourists in Puerto Vallarta are either being evacuated or moved into special hurricane "safe rooms" in their hotels.

Loudspeakers along the resort's shore warned people to leave, as did fire engines and ambulances that rolled through town blaring their sirens.

People in the nearby port of Manzanillo were also boarding up windows and laying sandbags.

British tourist Gordon Johnstone - in Puerto Vallarta - told Sky News he has been told the waves "could be as high as the third floor" and that they were being moved to a university.

"We're not getting enough information on when exactly we're going to be evacuated," he said.

"There has been some buses moved and evacuated other people - some Mexicans and different people like that - but not any UK people."

"They've handed out toilet paper and toiletries and pillows, so I wouldn't expect it's going to be that comfortable," added Mr Johnstone.

Flights into and out of the region have been cancelled, leaving many with no option but to ride out the storm.

Another tourist, Mike Fogarty, said: "This one seemed to come out of nowhere ... yesterday afternoon people were in the pool having a great time and it was like nothing was happening...

"Then the hotel passed notes under our doors - maybe about 9pm last night to let us know we may have to evacuate - it was pretty sudden."

Hotel worker Gabriel Lopez, in Manzanillo, said tourists would be well looked after.

"If there is an emergency we will take care of the people. There are rooms that are not exposed to wind or glass."

Dennis Feltgen, from the US National Hurricane Center, told Sky News there could be terrible damage: "Roofs are gone, walls are gone, buildings can literally be pushed off their slabs."

He said people would experience the worst of the storm for several hours.

"They'll get the catastrophic hurricane winds for an hour, hour and a half; then they'll get the calm eye as the centre passes right over them, then they'll get those catastrophic Category Five winds again coming from the opposite direction."

The storm is also set to have an impact on the US - millions of Texas residents are preparing for its remnants to reach the southern part of the state in a few days.