Millions have been warned to stay indoors, thousands are without power and trains have been cancelled as the Government’s “risk to life” alert brought on by Storm Darragh came into force.

The emergency alert came into effect at 1am on Saturday for people covered by the Met Office’s rare red warning for wind in parts of Wales and south-west England.

It was the largest use of the warning system yet, with the alert urging residents to avoid driving and to “stay indoors if you can”.

The Met Office confirmed to the PA news agency wind gusts of up to 92mph had been recorded overnight in Capel Curig in North Wales and Aberdaron on the Llyn Peninsula.

Gusts of between 72-78mph were recorded along the coasts of Wales and Northern Ireland.

Thousands of people across Northern Ireland, England and Wales were left without power as they braced for the storm’s impact.

As of 5am, National Grid reported more than 12,600 premises had lost power in the Midlands and south-west and more than 20,000 homes had been disconnected in Wales.

A note on the Northern Ireland Electricity Network’s website said the authority was unable to provide estimated restoration times.

“Due to the number of faults we are currently experiencing on the network, we are unable to provide an estimated restoration time for your electricity supply at this time,” it read.

“We are working to restore supplies as quickly and safely as possible.”

National Highways said both the Prince of Wales Bridge, M4 and the Severn Bridge, M48, which connect South West England to Wales were closed due to strong winds.

Network Rail Wales said all train services west of Cardiff were suspended until further notice due to falling trees blocking the line.

National Highways advised the QEII Bridge at Dartford Crossing in England’s south east had also been closed due to strong winds.

In the West Midlands, the A5 was closed between the B5070 at Gledrid and A483 at Halton due to strong winds.

The Met Office issued the red weather warning – the most serious type – on Friday for wind, meaning dangerous weather is expected and people are urged to take action to keep themselves and others safe.

The warning, which has led to the cancellation of events including Christmas attractions, is in place from 3am to 11am on Saturday.

The Met Office warned of “damaging winds” with gusts of 90mph possible over the coasts and hills of West and South Wales.

Forecasters say the strongest winds will begin to ease from late morning.

The Cabinet Office’s Emergency Alert system sent a message to every compatible mobile phone in the impacted areas, containing information about the red warning and guidance on how to stay safe into Saturday.

Mobile phones made a loud siren-like sound even if they were set on silent, with the sound and vibration lasting for about 10 seconds.

But some people have claimed they did not receive the alert.

A separate amber warning covering a larger stretch of the west coast of the UK, stretching from southern Scotland to Cornwall, and Northern Ireland is in place from 1am until 9pm.

Flying debris and falling trees could pose a risk to life while large waves and beach material could be thrown on to coastal roads and seafronts.

There could also be damage to buildings and homes, with roofs blown off and power lines brought down, as well as power cuts affecting other services such as mobile phone coverage.

Dublin airport confirmed it had welcomed a number of flights bound for other airports and were diverted due to the fourth named storm of the season.

A number of British airways flights to and from Heathrow, Paris, the United States and the Netherlands were also cancelled.

Darragh is also expected to bring heavy rain over the weekend, with more than 120 flood alerts in place on Saturday morning.

An amber warning for rain is in place in Wales from 3am to 6pm on Saturday with heavy rain likely to lead to disruption to transport and infrastructure.

A yellow warning for rain is in place for Northern Ireland and Wales, both of which were badly affected by flooding during Storm Bert, as well as parts of Scotland from 3pm on Friday until noon on Saturday.

The Met Office said periods of heavy rain in south and mid-Wales through Saturday are likely to see 20-30mm fall in three to six hours, with totals of 80-90mm possible by the time it begins to ease in the evening.

National Rail said the storm was likely to affect services across the whole network, advising people to check their journey in full before travelling as it may mean last services of the day are cancelled and passengers may not reach their destination.

Chiltern Railways advised customers to only travel if absolutely necessary on Saturday with significant disruption expected across the network.

A reduced timetable will be in operation with one train per hour on all routes. Chiltern said customers with tickets on Saturday can use them on Sunday, Monday or Tuesday instead.