The boss of a Windsor food bank has said the Prince and Princess of Wales are “welcome back any time” after they paid a surprise visit to help pack deliveries on Thursday.

Volunteers at Windsor Foodshare, who were only told an hour before William and Kate arrived on Thursday morning that the couple would be lending a hand, were impressed with how they got stuck in preparing food parcels.

On arrival at the food bank at Dedworth Green Baptist Church, the royal visitors were greeted by Windsor Foodshare chief executive Sarah Kember, the Rev Matthew Scott and church secretary Sandy Reynolds.

They then spoke with Windsor Foodshare’s founder, Sarah Howard, and Geoff Hudson, chairman of Windsor Christian Action, alongside Ms Kember and Rev Scott to discuss the food bank’s work.

During the 10-minute meeting Kate asked whether there are many food banks in the area, whether the produce is fresh, whether some people struggle with the stigma sometimes associated with food banks and whether young people are getting involved in volunteering.

William asked: “What is the hardest thing? How do you start setting up a food bank?”

They were then taken to the church where they helped a team preparing 98 food vouchers which can feed just under 200 people. Each parcel can feed a family for four to five days.

William packed food deliveries which feed a family of four while Kate checked food labels were in date.

At one stage when she was chatting to a group of four volunteers, William joked that they should pick up the pace and stop chatting.

He also joked with one volunteer that Kate usually does the shopping and laughed with another about knobbly vegetables.

Volunteers were “shocked” to find out they would be meeting William and Kate, and some worried that they had not put their make up on, but they said the royal couple put them at ease with their “natural” and “down to earth” manner.

Ms Kember said: “I had to tell them (the volunteers) a few porkies such as that we had a corporate visit or a school visit.

“They were such a lovely couple. They were down to earth and friendly, and really put us at ease.

“William was very neat at packing. They were interested in what happens in our local area and interested in how the food bank started and how we get donations.

“They are welcome back any time, we are always grateful for a pair of hands.”

Volunteer Linda, 72, who did not want to give her surname, told the PA news agency: “It was fabulous. We didn’t know until we got here, we had no idea.

“I asked William if he did the shopping normally and he said sometimes but usually Kate does it.

“They were very human and down to earth, very nice, asked lots of questions and were very interested. It is definitely something I will remember.”

Volunteer Emma Pilbrow told PA: “They were very natural and down to earth. I felt they wanted to be here and they showed a lot of interest.

“They asked where the food comes from and what happens to any vegetables that were left over. I also joked with them about knobbly vegetables.”

Windsor Foodshare was set up in 2013 and gives out food vouchers at the church between 1pm and 3pm every Thursday, and between 6pm and 7pm the same day at Kerith Community Church.