Millions of people in parts of Wales and south-west England have been told to stay at home as forecasters warn of a danger to life as Storm Darragh brings winds with gusts of up to 91 mph.

The Met Office has issued its highest-level red warning for potentially life-threatening weather. The alert is in place from 03:00 to 11:00 GMT on Saturday and covers western and southern Wales and the Bristol Channel coast.

The storm is likely to cause “significant disruption”, the Met Office said. Tens of thousands of homes are without power in south Wales and western England.

Around three million people received a government emergency alert on their mobiles on Friday evening giving advice about the storm.

The alert added that people should “consider gathering torches, batteries, a mobile phone power pack and other essential items you already have at home”, in case of power cuts.

Friday’s message was the largest use yet of the UK warning system and made a loud siren-like sound when delivered to devices, lasting for around 10 seconds.

“Being outside in high winds makes you vulnerable to injury. Stay indoors if you can,” it said.

Wind gusts of 93mph have been recorded in Capel Curig, north Wales, and 92mph in Aberdaron on the Llyn Peninsula.

Gusts of 80-90mph have been recorded around the Irish Sea since about 03:00.

It is unusual to see wind speeds this high sustained over a number of hours.

The most severe winds are expected on the western side of the UK as the storm moves south-eastwards across the country. They are expected to peak in the coming hours.

According to the National Grid, more than 22,000 properties were without power at 06:00 in Wales.

Across the Midlands and south-west England, power cuts were affecting more than 12,000 premises, National Grid live data showed.

Bristol Airport warned passengers that “disruption is expected” over the weekend and passengers are advised to check with their airline before travelling.

Cardiff Airport said it will not operate flights during the red warning and advised travellers to contact their airline or tour operator.

All rail services in the west of Cardiff have been suspended.

Nick Millington, a Network Rail route director, said multiple trees have fallen on the line.

“It’s a very dynamic situation,” he told BBC Radio 4’s Today programme.

Both bridges linking England and south Wales – the M4 Prince of Wales Bridge and M48 Severn Bridge – have been closed.

In Wales, all domestic football and rugby matches scheduled for Saturday have been cancelled, as has Cardiff City’s Championship fixture against Watford which had been due to kick off at 15:00.

Richard Griffiths, owner of the Richmond Hotel in Aberystwyth, said the town was in “complete darkness” following a power cut this morning.

All of London’s Royal Parks will be closed on Saturday, including the Winter Wonderland attraction in Hyde Park.

Horse races planned this afternoon at Aintree in Merseyside and Chepstow in south Wales have been abandoned due to the weather.

A Premier League match between Everton and Liverpool, scheduled at Merseyside’s Goodison Park, has also been postponed. It is the first top-flight derby to be cancelled because of the storm.

In Northern Ireland, where there is an amber weather warning until 21:00 GMT, multiple Christmas events have been cancelled this weekend.

Belfast City Council said its Christmas market would be closed on Saturday, while the Enchanted Winter Garden events at Antrim Castle Gardens had been cancelled for Friday and Saturday.

Storm Darragh is also expected to bring heavy rain over the weekend, with 120 flood alerts – meaning flooding is possible – in England.

There are 55 flood alerts in Wales, which was badly affected by flooding during Storm Bert and where the ground is still very saturated.

Amber weather warnings in Northern Ireland, Wales and western England are in place until Saturday morning, while other parts of the UK have lower-level yellow weather warnings.

Storm Darragh is the fourth named storm of the season following Bert and Conall which caused severe flooding last month.