Zara Tindall and Peter Phillips were at Princess Anne's estate when their mother suffered head injuries

Senior royals including the King and Queen, the Princess’s siblings and the Prince of Wales had been informed of the incident last night.

But it's understood that only Anne's closest family members - her husband, Sir Tim Laurence, as well as her two children, Peter Phillips and Zara Tindall - were at Gatcombe Park at the time.

While the movements of her children following the Princess's injuries are not yet known, a Buckingham Palace spokesperson confirmed that her husband, Sir Tim, accompanied Her Royal Highness to hospital.

Anne is currently receiving treatment, tests and observation at Bristol's Southmead Hospital - a cutting-edge NHS facility some 30 miles from her country residence in rural Gloucestershire.

The Princess Royal's equine run-in comes just days after she and her family appeared at Royal Ascot for a week of horse-racing festivities.

And Peter Phillips, her first son with former husband - and Olympic gold-winning equestrian - Mark Phillips, had been pictured alongside new girlfriend Harriet Sperling at the Berkshire racecourse.

READ MORE ON THE TINDALLS:

• Zara Tindall hugs grieving Lady Gabriella Kingston as royals rally around her at Ascot
  
• Zara Tindall is key for the Royal Family not to seem 'distant and out of touch'
  
• Mike Tindall shares rare loved up photo with Zara as royal couple wear matching pink polos
  

Phillips' relationship with Sperling was confirmed in May, with a source confirming he had met someone "recently" and they were "spending time together" following his shock split with his partner of three years, Lindsay Wallace, in April.

Phillips and Wallace had brought their relationship to a close because it had "run its course", while nobody external is believed to have been involved in their separation, according to the Sun.

Wallace had been in a serious relationship with the King's nephew and had been invited to several royal events including the late Queen's Platinum Jubilee celebrations.

Phillips shares two children with his ex-wife Autumn Kelly - but the couple ended their 13-year marriage in 2021.

Elsewhere at Ascot, Anne's daughter Zara Tindall had been spotted embracing Lady Gabriella Kingston, daughter of Prince and Princess Michael of Kent, after her husband died from a "traumatic head wound" in February.

On Tuesday, Zara was seen waiting at the parade ring for the royal procession to turn up alongside ex-rugby pro husband Mike Tindall, with Lady Gabriella arriving via coach with Princess Anne, Peter Phillips and royal racing manager John Warren.

Princess Anne and the Phillips' turnout at Ascot is to be expected - the Princess Royal is a noted equestrian, and has represented Great Britain on the world stage in both individual and team events.

While competing for her country, Anne suffered a concussion in 1976 - the same year in which she moved into Gatcombe Park - while participating in the Montreal Olympic Games.