Downing Street today called the week’s second Cobra meeting on the heatwave, as Britain prepares to endure temperatures of up to 39C (102F) from next Monday and the Government brings in contingency measures.

Cabinet Office Minister Kit Malthouse chaired the meeting of the Cobra (Cabinet Office Briefing Rooms) civil contingencies committee, which comes just three days after the first crisis meeting was held on Monday.

The Prime Minister’s spokesman said the move was a ‘progression’ of the ‘significant work ‘ that had already been done to prepare, and there were contingency measures which have been enacted or are ready to be enacted.

It comes as river levels are at 30 per cent of normal levels, farmers are using a third more water and Britons have been told to take shorter showers after the lowest rainfall in more than a quarter of a century in parts of the UK.

Farmers warned today of a ‘significant challenge’ posed by the extremely dry weather as they try to keep crops fully watered in the face of rising fuel, electricity and fertiliser costs during the heatwave gripping Britain.

East Anglia is particularly parched this summer after it saw just two thirds of its normal rainfall in the first half of 2022, making it the region’s driest six-month period since 1996 and the 11th driest since records began in 1836.

Some rivers in the area are drying out – such as the River Waveney which is at only 30 per cent of its normal flow – while millions of households in Yorkshire have been urged to cut water use or face the prospect of a hosepipe ban.

The Environment Agency has classified the Waveney’s flow rate as ‘exceptionally low’, while the River Great Ouse in Ely, Cambridgeshire; the River Yare in Norfolk; and the Little Ouse in Thetford are all now labelled ‘notably low’.

Yorkshire Water has said it cannot rule out a hosepipe ban and is urging residents to spend at least one minute less having a shower – suggesting singing Bon Jovi’s Livin’ On A Prayer to reduce their time to four minutes.  Bookmaker William Hill is offering 3/1 on a hosepipe ban to start in the next six weeks, for the first time since 2012.

One farmer on the Norfolk/Suffolk border said he would normally budget £80,000 for electricity to pump water around his crop fields, and this had already gone up to £250,000 this season. But this is now set to increase to £300,000 because of an extra 25 to 30 per cent of water that he is having to pump due to the very dry weather.

Yesterday, the Met Office extended its extreme heat warning to last from Sunday until the end of next Tuesday for most of England and Wales amid warnings of chaos on transport networks and in the NHS and other services. 

But there will be some temporary respite, with today set to be the first day since July 9 that temperatures have not got to at least 30C (86F) in the UK, with highs of 27C (81F) to 29C (84F) expected between today and Saturday.

However the amber warning then begins at midnight on Saturday night, with highs of 33C (91F) forecast on Sunday before the peak of the heat on Monday and Tuesday when up to 39C (102F) is expected in London.

The Met Office confirmed today that ‘exceptional heat is possible for southern and central areas of the UK late this weekend and early next week, with temperatures likely in excess of 35C (95F) in some places’. 

Ministers and officials have been drawing up plans with the NHS and councils, with ambulance trusts on high alert. The Prime Minister’s spokesman said there were ‘tried and tested’ plans in the NHS for increasing staffing in relevant areas, adding: ‘There have already been some co-ordination meetings at official level across Government.

‘This is a progression of that to ensure that – as we come into what are predicted to be the hottest days – that the necessary mitigations and actions are in place or being but in place. A lot of this is making sure the public are aware of the advice that is available – particularly those with young children or vulnerable family members.’

After chairing the Cobra meeting, Mr Malthouse said the Government is preparing for a ‘surge’ in demand on the NHS and other services and that the public should look out for people who are particularly vulnerable in the heat.

He told BBC Radio 4’s The World at One: ‘The key thing we can do is prepare the Government services for what may be a surge in demand – not least the health service and elsewhere – but also critically communicate that the first line of defence is actually individual behavioural change. People need to take care, do all the stuff they would do when it is very hot – wear a hat, drink water – but critically also (with) the most vulnerable groups – the elderly, those with cardiovascular problems and the very young – that people look out for them and take care. 

‘We are asking people if they have an elderly neighbour, particularly if they live alone, it would be a neighbourly thing to check up on them and make sure they are looking after themselves and have access to water. The current forecast is that we will be in the mid to high-30Cs but there is a smaller possibility that we could exceed that and possibly hit 40C which would be an all time record.’

Some workers are looking forward to some bonus time off – with David Davies, the owner of drinks exporter Sovereign Beverage Company in Blackburn, Lancashire, giving all staff the day off next Monday to enjoy the heat. 

Meanwhile all steam locomotives have been suspended on the Severn Valley Railway between Bridgnorth and Kidderminster until at least next Tuesday because the hot and dry weather ‘poses a significant risk of fires being started by cinders escaping from the engines’ – with services instead being hauled by heritage diesel locomotives.

And a series of summer events from fairs to markets and carnivals to dog shows are being cancelled across the country due to the heat – including a cheese market in Chiswick, West London, and a dog show in Bude, Cornwall.

Also cancelled this weekend are a school fair in Steeple Bumpstead, Essex; a carnival in Hungerford, Berkshire; an animal sanctuary event in Lincolnshire; a brewery open day in Silchester, Berkshire; and various country walks. It follows a series of sports days being cancelled at schools this week due to the weather being too hot for children. 

The Welsh Government said all organisers should ‘assess whether all or part of the event should be postponed’ after considering ‘additional communications’ for attendees ‘on recommended safe behaviours’ and whether any shade, water stations and other measures can be imposed ‘to mitigate against the worst effects of extreme heat’.

Despite the heat, June 17 still stands as the hottest day of 2022 so far when 32.7C (90.9F) was recorded in London. The UK’s highest ever temperature was 38.7C (101.6F) in Cambridge on July 15, 2019 – and the Met Office said there is a 20 per cent chance this will be broken, but that is down from a figure of 30 per cent given earlier this week.

An Environment Agency spokesman told MailOnline: ‘Dry weather this year has led to receding river flows across much of England and Reservoir levels falling across Yorkshire, central and southwest England. Hot weather will increase pressure on our water environment and wildlife. We are working with water companies and other abstractors to monitor water resources and ensure the needs of water users and the environment are met. We can all do our part to use water wisely, reduce our usage and manage this precious resource.’

Also today, weather expert John Hammond told GB News: ‘I think there will be hundreds of thousands of excess deaths early next week. The charts that I can see in front of me are frightening. We all like nice weather but this will not be nice weather, this will be potentially lethal weather for a couple of days. It will brief, but it will be brutal.’

BBC meteorologist Mr Hammond added: ’40C is the sort of temperature that this country, I’m afraid, is just not geared up to cope with. So if you’re an employer, I’d be worried about early next week how your workers are going to safely get to work. And if you’re an employee, then I would be asking my employer with potentially railway lines going buckled and lots of infrastructure disruption, how am I going to get to work, should I be getting to work?’

Andrew Blenkiron, director of the Euston Estate near Thetford and chairman of the National Farmers Union in Suffolk, told BBC Radio 4’s Today programme this morning: ‘We grow winter cereals here – so that’s wheat and barley, we grow sugar beet for a British Sugar factory just down at Bury St Edmonds.

‘And we grow about 1,200 acres of irrigated root crops – so that’s parsnips, potatoes, carrots and onions, and that’s where our significant challenge has arisen at the moment to try and keep those crops fully watered to ensure that they meet market specifications and indeed generate a yield.

‘We started irrigating our crops here very early this year in the beginning of April.

‘But it’s been this last two week period where evapotranspiration rates have been so incredibly intense that water has just poured through the crops.’

He said there are three main cost increases – those being the doubling of fuel costs for the tractors to plant the crop, harvest the crop and look after it; the tripling of fertiliser costs; and the trebling of the electricity cost associated with pumping all of that water around.

As for electricity costs, Mr Blenkiron said: ‘A usual season we budget about £80,000 for that. This season I’ve had to budget £250,000 – that three-fold increase. 

‘But because of this extra 25 to 30 per cent water that we’re having to pump round at the moment, that electric bill is going to run to well over £300,000 which is the challenge that’s occupying my mind.’

He added that supermarkets are ‘not that enthusiastic to increase their prices’, particularly for the root crops – and the contracts for those were agreed before Russia’s invasion of Ukraine and the recent surge in gas prices.

Mr Blenkiron also said he hoped farmers would have the power to put prices up when contracts are renegotiated in autumn, adding: ‘What’s going to happen this next season if we don’t see some reasonably strong increases in our prices that people just won’t plant those crops next year.

‘They’ll turn to another crop, a winter cereal or something like that – so considerably less investment per acre and considerably less risk.’

Meanwhile, water bosses said customers should take shorter showers and avoid leaving taps running.

Water shortages are said to be worst in Yorkshire, where five million people have been given urgent advice to cut down on how much they use. 

Neil Dewis, from Yorkshire Water, said the amount stored in reservoirs had dwindled to levels last seen in 1995 – when supplies ended up being brought to the area by hundreds of tankers.

He said restrictions such as a hosepipe ban could not be ruled out, describing them as ‘just one of the tools’ the company could use.

Customers in London were also urged to cut down on use by Thames Water, with tips including taking shorter showers and using watering cans instead of hosepipes to keep gardens green.

‘While we’re not currently expecting to introduce restrictions on water use this summer, it’s important that households remain responsible with their usage and help us to limit the pressure on our resources,’ said its demand reduction manager, Andrew Tucker.

Households in England and Wales have not seen a ban on using hosepipes enforced for ten years, but South East Water did urge customers to stop using them during a 2020 heatwave.

However its head of water resources, Lee Dance, yesterday insisted reservoir and groundwater stores remained healthy.

But with domestic usage 50 per cent higher than normal during the hot spell, he urged customers