Over Christmas he spent three weeks at Sandringham with his family

William filled his helicopter up with fuel after returning from rescue mission

The helicopter landed in the grounds of John Henry Newman School

Prince William tucked into a roast chicken dinner alongside school pupils in their canteen when he stopped for a break between shifts with the East Anglian Air Ambulance today.

Students were stunned to see the Royal in their canteen at break time, after he had landed his helicopter in the school grounds.

The second in line to the throne returned to his duties after the Christmas holiday yesterday and is back working alongside colleagues at his local air ambulance service.

William, who visited John Henry Newman School in Stevenage with two colleagues, later paid his compliments to the chef, Stuart.

Clive Matthew, headteacher, said: 'The school is close to the Lister Hospital so the helicopters use the playing field to land and we always offer the crew refreshments.

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Dinner time: Prince William tucked into a roast chicken dinner alongside school pupils in their canteen

Stunned: Students were stunned to see the Royal in their canteen at break time at John Henry Newman School in Stevenage, Herts,

Compliments: Prince William did not have a pudding, but later paid his compliments to the chef

Spontaneous: Headteacher Clive Matthew said the visit 'made the students' year'

'We were stunned when we realised Prince William was part of the crew today.

'He sat with me and some year 11 pupils and they asked him if he had enjoyed the Christmas holidays and he told the students he'd had a lovely time.

'He was really nice and it was lovely the visit was so spontaneous. I think it made the students' year,' said Mr Matthew.

Shocked: Year 11 pupils soon started tweeting and posting photos of their famous visitor

Formula One driver Lewis Hamilton and England International footballer Ashley Young both attended the Hertfordshire school.

The Duke of Cambridge recently moved to a new purpose-built base in Cambridge International Airport as part of his work with the East Anglian Air Ambulance.

The 33-year-old Royal was earlier seen dressed in a high-visibility jacket, filling up a helicopter with fuel in preparation for his next rescue mission.

Lunch date: Prince WIlliam stopped in at John Henry Newman Catholic School for a roast chicken dinner today

Alumni: Both Formula One driver Lewis Hamilton and England International footballer Ashley Young attended the Hertfordshire school

Close: Prince William visited the school with his two colleagues. The school grounds are often used as a landing pad for helicopters due to its proximity to Lister Hospital

Hard at work: Prince William was seen yesterday filling up his helicopter with fuel after returning to his job as an air ambulance pilot

Inspection: The Duke of Cambridge checked his aircraft after flying out on a mission

Yesterday he was up at the crack of dawn for his first shift after a three-week break for Christmas, and is believed to have flown on several missions in the course of the day as well as carrying out maintenance work.

As he landed at the base - not far from the home in Anmer Hall where he lives with the Duchess of Cambridge and their children George and Charlotte - he inspected his aircraft along with other workers.

He then headed into the new two-storey base, which provides more home comforts than the previous staff quarters in a small room at the back of the main airport building.

William was seen sporting a close-cropped haircut at the weekend in preparation for his return for work.

He and the rest of the Royal family recently hosted Kate's family, the Middletons, and the in-laws all attended church together at Sandringham on Sunday.

Duties: The Prince is based at Cambridge International Airport in a new purpose-built headquarters

Safety: The Royal was wearing a high-visibility jacket as he went about his duties at the base

Employee: William gives his East Anglian Air Ambulance salary to charity

The Duke had been spending Christmas with the Queen and other relatives, relaxing and bonding with his eight-month-old daughter.

William has been working for the air ambulance service since last summer after leaving the RAF, where he flew search and rescue helicopters for several years.

The fleet is currently settling in to its new £250,000 base, just 100 yards from the helicopter pad where the Duke landed yesterday.

The new building features sleeping accommodation and a canteen, with a toaster - which was not allowed in the old staff room because of safety fears.

Work do: Over the weekend William was seen with a shorter haircut in preparation for his return to duty

Family: The Duke and Duchess of Cambridge posed with their children for a Christmas photograph

The quarters also have special sound-proofing which helps the pilots relax by cutting down on noise from the airport.

It is believed the new base could shave up to a minute off response times as crews can land right outside the building. They aim to be airborne within four minutes of receiving a call.

William, who donates his salary to charity, is on a roster of day and night shifts which last nine and a half hours.

He flies an EC145 T2 aircraft and responds to emergencies in Norfolk, Suffolk, Cambridgeshire and Bedfordshire, ranging from road accidents to heart attacks.