Princess Charlotte had a “lovely birthday” and is growing up “very fast”, proud father the Duke of Cambridge has revealed.

William said another family was invited to celebrate his daughter’s big day over the weekend, when he toured an engineering firm in the West Midlands.

Jenna Jackson, a mother of two and lead HR business partner with Babcock Vehicle Engineering, quizzed the duke about Charlotte – who celebrated her sixth birthday on Sunday.

“She had a lovely day thank you,” William replied, “Last year it was her birthday in lockdown but this year we were able to have one other family over.

“They grow up very fast. It was great fun.”

In a new picture released to mark the princess’ birthday, a confident Charlotte smiles in the photograph and sports highlights in her long hair.

William went to Babcock to recognise the work the company has done in keeping the police, military, air ambulances, other emergency services, civil service and other organisations running during the coronavirus pandemic.

The company has also produced ventilators for the NHS during the health crisis, and made air ambulances Covid secure by fitting screens.

Earlier, the duke opened Aston Villa’s new training ground and paid tribute to Ron Smith, the father of Dean Smith – the football club’s manager, who died last year aged 79, after contracting Covid-19.

William said Ron Smith, a lifelong Villa fan like the duke, would have been “very proud” of the achievements of his son who has steered the team to promotion and Premier League safety since being appointed in 2018.

During his visit to Babcock in Walsall, the second in line to the throne met some of the 289 staff in the workshops, and spoke to engineers who fit blue lights, sirens, computers, radios and other specialist equipment to police cars.

One group told him they work on cars for Scotland Yard’s royalty protection department.

“We’re always breaking your vehicles,” William joked and when one of the group asked him if he was a fan of his police bodyguards’ cars, the future king risked a bumpy ride home.

“The guys really rate them,” he said, before joking: “Some of their driving skills need to be questioned.

“Don’t tell them I said that.”

The duke also talked to staff about the challenges they have faced during the pandemic.

Jason Price, director of vehicle engineering, said the firm had been forced to change some of its production processes, requiring engineers to work alone on a vehicle instead of in a team.

In the early days of lockdown the company was forced to furlough some staff when car manufacturers or other suppliers shut down. There were also times when Covid-19 hit the workforce.

“We had a few people who were, unfortunately, quite poorly but thankfully they all pulled through,” Mr Price said.

He added: “What we are really proud of is the fact that we have kept working throughout the pandemic.”