UK weather forecast: Met Office issues double thunderstorm warning as Britons face 'disruptive' Sunday

The first warning will impact Northern Ireland from 10am to 9pm.

It could result in flooding, lightning, hail and strong winds.

The Met Office said: "Showers and thunderstorms, likely frequent in some areas, may bring some heavy downpours to parts of Northern Ireland, perhaps accompanied by hail and lightning.

"In some places showers may become organised at times to give longer spells of wet weather.

"Where showers are most frequent, or becoming more organised, there is the potential for 25-35 mm of rain in two or three hours."

The second warning, which is in place from 11am to 8pm, could lead to travel delays and will impact large swathes of South West England and Wales.

The UK's national weather service added: "Areas of heavy showers and thunderstorms are likely to form over parts of southwest England and Wales during Sunday.

"Whilst the majority of these will move through fairly quickly, giving short-lived downpours or thunderstorms, there is a chance of them lining up with a few spots potentially seeing repeated bouts of heavy rain and thunder.

"Where this happens some disruption could occur with up to around 25 mm of rain falling in an hour and perhaps 40 mm in two or three hours.

"Frequent lightning, hail and a few strong wind gusts could accompany these storms."

Flood alerts are already in place across parts of the United Kingdom.

England's Environment Agency issued a total of 29 flood alerts.

A further 16 flood alerts and one flood warning has been issued north of the border, the Scottish Environment Protection Agency has said.

Temperatures across the UK will hover around the high teens and low twenties throughout today.

London will witness mercury hit 22C.

Manchester and Glasgow will fall slightly behind on 21C.