Standing barefoot in a floral headband and staring into the eyes of her new husband, Carrie Symonds - now Johnson - defied the traditional trappings one might associate with the wife of a Prime Minister. Surrounded by hay bales, colourful bunting and lanterns in the garden of No 10, the couple opted for a bohemian festival-style celebration after tying the knot in secret on Saturday.

But as the first unmarried couple to live together in Downing Street, and the first Prime Minister to wed whilst in office in almost 200 years, the Johnsons are not shy of breaking with tradition.

After much speculation about their nuptials and a save-the-date for July 30, 2022 card sent just six days before they tied the knot, people were expecting an elaborate affair. But in the end Mr Johnson’s third marriage was low-key, with guests dancing to Don McLean’s American Pie played by a wandering acoustic fiddle band. The event has been meticulously planned in secret for the past six months, and even the small number of guests allowed under Covid restrictions were only told at the last moment, it is understood.

The day began in Westminster Cathedral when, shortly after 1.30pm, confused tourists were ushered out of the building on the basis that it was going into lockdown. Just 30 minutes later Ms Symonds, who has since taken her husband’s name, swept into the piazza in front of the cathedral in a limousine, wearing a pounds 2,870 embroidered tulle gown but no veil.

Close friends and family and their year-old son Wilfred watched as they were married by Father Daniel Humphreys, the head of the cathedral.

He had baptised their son six months earlier in the same Lady Chapel, an ornately decorated room that hosts morning and evening prayer. He had told the couple “over many months” to ensure they were both prepared for the marriage.

After the ceremony the guests - which it is understood included Mr Johnson’s siblings Rachel, Jo and Leo, his father Stanley and half-sister Julia - were whisked to Downing Street.

The first official photograph was released yesterday morning (Sun) and showed the couple embracing in the garden. Mr Johnson had even appeared to have brushed his famously unruly hair, though his tie remained askew.

They opted to hire Rebecca Fulton, an external photographer, rather than Andrew Parsons, a special adviser who takes official pictures. The Oxfordshire-based photographer’s prices are about pounds 2,300 for a wedding shoot, although the Prime Minister may have received a bargain rate as the ceremony was brief.

But it was a photograph later posted on social media by Conservative MP James Cleverly that painted a more intimate picture. With his black suit jacket removed, top button undone and sleeves rolled up, Mr Johnson, 56, was seen with his arm around his new bride, who stood barefoot on the lawn.

Mrs Johnson’s dress, by Greek-based designer Christos Costarellos, with a tiered skirt, fitted bodice, bell sleeves and latticework trims, has already sold out online.

Mr Cleverley’s photograph was one of the few peeks inside a party that remains shrouded in secrecy, with one attendee joking there was an effective “total omerta” on talking about it when approached by The Telegraph.

Staff at the reception were made to sign non-disclosure agreements with an “extensive” list of details they must keep secret after the event. But this newspaper has established the couple treated their guests to music from the London-based trio Fiddlin’ About.

The band describes itself as a “high energy acoustic wandering band” that mingles with guests, taking requests. It features The Proclaimers’ I’m Gonna Be (500 Miles) on its track list, alongside Teenage Dirtbag and Seven Days.

Online, the group says it can provide “anything from raucous singalongs to tasteful background music”, and charges pounds 1,750 for a three-hour set and claim to have performed to the Duke and Duchess of Sussex. Also in the band’s repertoire is one of Mr Johnson’s favourite songs, Van Morrison’s Brown Eyed Girl.

The Prime Minister told the BBC’s Desert Island Discs in 2005 that “you can have too much of Van Morrison” but named the “cheery” song as one of his favourites. Fittingly, brown is the colour of his new wife’s eyes.

Guests were pictured leaving No 10 later that evening. Among them was Hugo Dixon, an ardent Remainer, who has known Mr Johnson since their days at Eton together.

His appearance, in a gold waistcoat, came as somewhat of a surprise given that in 2019 he wrote an open letter to Mr Johnson in the Guardian calling on him to halt Brexit and noting that they had “grown distant”, in part because of their views on leaving the EU.

As the wedded couple were only allowed 30 guests, there were some notable absences including John Whittingdale, for whom the new Mrs Johnson worked as a special adviser when he was Culture Secretary. He was in the loop about the ceremony but did not attend.

Sajid Javid, another former Tory cabinet minister who Mrs Johnson advised, also did not attend.

It has been speculated that Mrs Johnson’s friend Dixie Maloney, a corporate events organiser, had planned the day. It appears that Downing Street aides were just as shocked as the public to discover that their boss had married.

“It was a total surprise, totally unexpected”, said one No 10 adviser who had been in the building the day before and saw no evidence of the imminent nuptials.

“There were no deliveries. I don’t remember any signs of prep. It was all choreographed in such a way that there were no giveaways,” the source told The Telegraph.

They added that they had “complete admiration” for how the event had been kept under wraps so successfully, stating: “It’s been a magnificent example of forward planning.”

Telegraph Media Group Limited [2021]