A billionaire's grand plans to renovate a sprawling 100-bed mansion have hit a snag - a fungal discovery within the walls has prompted new planning submissions.

Chris Rokos, hedge fund magnate, who had previously been on the receiving end of a warning for commencing renovations on his vast 4,500-acre estate near Marlborough, Wiltshire, without the green light from planners, is now grappling with an unexpected hurdle.

His ambitious renovation includes an underground passage linking the 1820s country house, the nearby stables, and a planned pool house.

However, this month has seen a twist in the tale as architects unearthed fungus lurking in the walls of the Grade I-listed building, necessitating fresh plans.

An architectural survey revealed that some plasterwork on the first floor was in a state of 'complete decay', with ominous 'dry/wet rot fruiting bodies' nestled within wall cavities.

The newly submitted plans are a response to existing permissions which dictate that historic plasterwork must be preserved.

Alarm bells have rung for 10 areas on the first floor, which includes over 30 rooms, corridors, and staircases.

Architects have now concluded that "more significant repair and replacement works are now required in specific areas which would not fall under the scope of like for like patch repairs consented."

The storied Tottenham House, once presided over by the Earl of Cardigan David Brudenell-Bruce, left family hands after 200 years when it was sold to a developer in 2014 for a hefty £11.25m.

Tottenham House, part of the historic Savernake Estate, traces its roots back to the Norman Conquest when it served as a Royal Hunting forest.

The first mention of a house at this location was during Henry VIII's visit to Sir John Seymour at Wolf Hall, with members of the Seymour family reportedly staying at Tottenham Lodge.

Henry VIII met his future wife Jane Seymour at Wolf Hall and married her in 1536, which elevated the status of the family and led to the estate being transferred into the Seymours' personal ownership in 1547.

The estate was later passed down through the female line of the Seymour family to the Bruce family, who became known as the Brudenell-Bruces.

However, the current Earl of Cardigan, David Brudenell-Bruce, lost ownership of the house in 2014 following a legal dispute with trustees.