The Queen was left amazed by a new £20 million teaching centre created in the historic grounds of one of the capital’s Inns of Court.

The monarch was joined by the Duke of York for the visit to Lincoln’s Inn and after touring the subterranean Ashworth Centre, and being shown its well-lit lecture auditorium, she said: “Amazing – really light underground.”

Named in honour of Mercy Ashwoth, one of the first female members of the Inn to practise as a barrister in England and Wales, it was excavated over two floors during a two-year project.

Royal visit to Lincoln’s InnThe Queen at The Honourable Society of Lincoln’s Inn in London (Toby Melville/PA)

After the Queen’s comment Lord Justice Patten, treasurer of Lincoln’s Inn, joked with the monarch saying: “We’re like Russian oligarchs who dig underground.”

Lord Justice Patten said after the visit: “She was very surprised, we were able to get as much into the space, and also how deep we’ve been able to excavate because it’s two floors down.

“This is a very sensitive site, we can’t just put a building up in the garden, so the only option we had to was to dig down under the terrace.”

Lincoln’s Inn is one of the capital’s historic four Inns of Court alongside Gray’s Inn, Inner Temple and Middle Temple, and is home to a number of barristers’ chambers and solicitors’ offices.

The new centre, which will welcome its first students sometime after Easter, will provide the inn with much-needed space for teaching, lectures and meetings to aid the education of future barristers.

During the visit the Queen was shown a rarely seen portrait of her late sister Princess Margaret, a former Royal Bencher or patron of Lincoln’s Inn.

She was painted in 1970 by the artist Bryan Organ who went on to create a series of ground-breaking royal portraits of the Duke of Edinburgh and the Prince and Princess of Wales.

During the visit the Queen also re-opened the Great Hall. Following light renovation, the building is the physical and symbolic centrepiece of the inn and was first opened by Queen Victoria on October 30 1845.

Royal visit to Lincoln’s InnThe Queen tours the facilities (Toby Melville/PA)

In the hall the Queen and Andrew, a Royal Bencher of Lincoln’s Inn, met tutors, education committee members, past treasurers, senior benchers and key members of staff.

When the Queen left at the end of the visit she was given a posy by Evie Hayden, aged four, from Kent, who had been plucked out of the crowds with her mother Michelle Hayden, 33, to make the presentation.

Royal visit to Lincoln’s InnEvie Hayden and her mother Michelle present the Queen with flowers (Toby Melville/PA)

Mrs Hayden, whose husband is a barrister based at Lincoln’s Inn, said the pair had an ordeal to get to London: “Typically I missed a train then had a delayed train, my daughter fell over and scuffed her tights but we made it.”