Prince William had a three-week stint as a spy and even went on undercover jobs

PRINCE William became a royal 007 for a stint as a spy — and went on undercover surveillance jobs.

The future king has just been on secondment with Her Majesty’s Secret Service, joining MI6 plus MI5 and GCHQ.

He spent a week at each and his work included watching out for terror plots.

And sources revealed the Duke of Cambridge’s jokes had been a huge hit with the spooks as they worked to keep the country safe.

One revealed: “The Duke wasn’t just watching from the sidelines. He was fully immersed at times on undercover surveillance operations, not just sitting in front of a computer in an office.

“He impressed everyone with his professionalism — and his sense of humour.

“He spent most of his time with ordinary rank and file workers, not just the bosses, and sat with them in the canteen to join in their discussion.”

The Sun on Sunday understands royal aides had asked spy chiefs if he could get an insight into their hush-hush world.

‘VERY IMPORTANT AS FUTURE KING’

The request was quickly granted and Wills, 36, started his duties at MI6, the Secret Intelligence Service, last month.

He then moved on to two further postings at the Security Service MI5 and GCHQ, the government’s listening station.

A source said: “He feels it’s very important as future king that he followed up from his time in the military to find out as much as possible and understand the role played by people working to defend us here at home.”

While in London, Wills did a full working day after completing the school run.

But he still managed to fit in some royal duties, dashing off from MI5 to hand England ace Harry Kane his MBE during a ceremony at Buckingham Palace.

He is understood to have commuted from Prince Charles’s Highgrove estate while at GCHQ’s base — dubbed The Doughnut — in nearby Cheltenham, Gloucs.

As second in line to the throne, he did not need security clearance to see classified material.

And during his spell at MI5, he worked alongside counter-terrorism teams analysing threats to the UK from groups such as Islamist terror cells.

UNDERCOVER SURVEILLANCE

The Duke is understood to have made a speech to staff at the end of his MI5 posting, thanking them for the work they do. A source added: “He was insistent that everyone, no matter how junior, call him William and not Sir. It was impressive and he took a genuine interest. He views these experiences as essential in preparing him for becoming the next Prince of Wales.”

Both Wills and Kate have visited security and intelligence services in recent years.

But this is thought to be the first time a member of the royal family has worked for them. Dad Charles, 70, worked in government placements when he was younger to learn more about the Foreign Office and No10.

William said last night: “Spending time inside our security and intelligence agencies, understanding more about the vital contribution they make to our national security, was a truly humbling experience.

“These agencies are full of people from everyday backgrounds doing the most extraordinary work to keep us safe.

“They work in secret, often not even able to tell their family and friends about the work they do or the stresses they face.

“They are driven by an unrivalled patriotism and dedication to upholding the values of this country. We all owe them deep gratitude for the difficult and dangerous work they do.”

GCHQ’s head of counter-terrorism, known only as David, added: “Having The Duke of Cambridge spend time with our teams was an incredible opportunity.

“William worked exceptionally hard to embed himself in the team and comfortably held his own amongst some highly skilled analysts and operators. His Royal Highness asked some probing questions and demonstrated a real grasp of our mission.”

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