Thunderstorms and 30°C temperatures are expected on Sunday, after the UK saw its hottest day of the year on Saturday.

The Met Office issued a yellow warning for thunderstorms from 12:00 until 21:00 BST on Sunday for Wales, Northern Ireland and most of western and central England and Scotland.

It warned of heavy rain, hail, strong winds and lightning in some areas.

On Saturday, temperatures reached 30.4°C in Surrey.

The Met Office had been expecting up to 100mm of rain on Saturday evening, which equates to a month’s worth of rain, but the most recorded was 21.8mm in Billinge Hill, Merseyside.

It said there was a small chance that homes and businesses could be flooded quickly on Sunday, with damage to some buildings from floodwater, lightning strikes, hail or strong winds.

Delays and some cancellations to train and bus services could happen as a result of any flooding or lightning strikes, it added.

Difficult driving conditions could also be expected as a result of spray and sudden flooding and there is a slight chance of power cuts.

The UK Health Security Agency issued an amber hot weather alert until 09:00 BST on Tuesday for much of south England and the Midlands.

It means high temperatures could affect all ages and impact the health service.

Temperatures reached 27.6°C in Auchincruive, Ayrshire, on Saturday – making it the warmest day of the year in Scotland.

A temperature of 30.4°C in Northolt, west London, and Wisley, Surrey made it the UK’s hottest day of the year too.

On Sunday, there is likely to be more cloud – with maximum temperatures of 32C, the Met Office said.

It forecasts that next week, the risk of thundery downpours will continue in some areas and temperatures are likely to remain above average.

Most of the UK will meet heatwave criteria next week, the Met Office added.