Image copyright Getty Images Image caption Flour has been in short supply in supermarkets

With the nation confined to their homes amid the coronavirus lockdown, a rise in home baking appears to be contributing to shortages of flour on supermarket shelves.

Grocery sales of flour were up 92% in the four weeks to 22 March compared to the same period last year, according to consumer analysts Kantar.

The National Association of British and Irish Millers (Nabim) says the industry is "working round the clock", milling flour 24 hours a day, seven days a week to double production - but is still struggling to meet demand.

At Wessex Mill in Oxfordshire, the family business is running at 24-hour operation for the first time in its 125-year history.

Record traffic to their online shop has also forced them to close it down and only open for 10 minutes a day.

"It's unprecedented," says Emily Munsey, who runs the mill with her father. "We've increased production about four-fold but we're nowhere close to meeting the demand we've seen."

After losing about 15% of their staff because they are self-isolating the business has even recruited local people who are out of work because of the lockdown, including builders and chefs, to replenish its workforce.

Image copyright Wessex Mill Image caption Emily Munsey has been working 12 hour shifts to try and keep up with demand

Alex Waugh, director general of Nabim, says the issue isn't being able to mill enough flour - but the lack of capacity to pack it into small bags for retailers.

Only around 4% of UK flour is sold through shops and supermarkets, according to the association. The majority is produced in bulk and delivered in tankers or bags of more than 16kg to bakeries or other food manufacturers.

However, since the coronavirus outbreak, Nabim says ordinary shoppers have been purchasing much more flour than normal - with existing stocks quickly used up.

Mr Waugh says packing lines are now running at maximum capacity but this is only enough for 15% of households to buy a bag of flour per week - and existing packing lines can't easily be adapted to produce smaller retail bags.

One option the industry is considering is the possibility of shops selling larger bags - as it is better equipped to produce in bulk.

However, Mr Waugh says that could be some way off and for now it's just a question of waiting for demand to reduce enough for stock levels to be rebuilt.

So why the sudden increase in demand?

As well as the public generally stocking up on non-perishable goods amid the lockdown, a rise in home baking also appears to be a factor.

At Wessex Mill, Ms Munsey says they have been overwhelmed by members of the public ringing up trying to source flour for recipes.

"We've had to get an extra person in the office and take down the phone number from our website because we were getting so many people who normally buy flour in the supermarkets ringing round flour mills," she says.

Online searches for bread and cake recipes have surged since mid-March, when restrictions on life in the UK first began to be introduced, according to Google Trends.

And BBC Food has seen record traffic since the start of the lockdown, including a 540% increase to its banana bread recipe - the site's most popular recipe at the moment.

Traffic to its basic bread recipe is also up 875% and as stocks have depleted a page on how to make bread without yeast or bread flour has seen a surge in popularity.

Image copyright Katherine Rhodes Image caption Katherine has been baking with her daughter Beatrix

Katherine Rhodes, 36, is one of those who has turned to baking to keep her two young children occupied at home.

Living in a rural part of Essex, there is no shop nearby so making her own supplies was also a way to avoid leaving the house as much as possible.

Like others, she's had trouble getting hold of flour - but managed to source some from her local bakery.

"They put out a message on social media two days ago saying they were going to source flour direct from the mill and divvy it out to local residents," says Katherine. "The response was astounding," she adds, with the bakery overwhelmed with interest.

Image copyright Zoe Lacey Image caption Zoe and her son have been enjoying freshly baked bread every couple of days

Zoe Lacey has also taken up baking to fill her time during the lockdown.

The 36-year-old had never made bread in her life - but when she couldn't find any in her local shop last week she decided to try making her own.

"It was the most delicious bread I've ever had so we're hooked," says Zoe, who is now on her fifth loaf.

"I managed to find the last bag of flour on the shelf last week so I'm hoping I'll be able to find more on my next shop - otherwise my bread journey might be over!"