Frogmore Cottage renovations: Harry and Meghan's country retreat in Windsor had major six-month overhaul at cost of £2.4m to taxpayer

The extent of the Duke and Duchess of Sussex's renovations at Frogmore Cottage, close to Windsor Castle has been revealed, with the property being substantially modernised and renovated — at a cost of £2.4 million to the taxpayer, according to royal accounts.

Major work turned five properties back into a single home for Harry and Meghan over the course of six months before their son Archie was born on May 6, although some works — including a repaint of the exterior — remain to be completed.

It is likely Harry and Meghan installed a luxury kitchen and bathroom in their country residence, and it has reportedly been fitted out with a mother-and-baby yoga room, complete with a "floating" or sprung wooden floor that replaced Victorian floorboards.

All fittings and fixtures were privately paid for by the duke and duchess but accounts for the Sovereign Grant, which funds the Queen and her household's official expenses, show the monarchy cost the taxpayer £67 million during 2018-19 — an increase of almost £20 million on the previous financial year.

A large amount of the rise was due to work updating the decades-old services at Buckingham Palace and maintaining the occupied royal palaces.

The Core Sovereign Grant which helps fund the work of the Queen and her household, and pays for other activities like official royal travel, increased by £3.6 million to £49.3 million.

Sir Michael Stevens, Keeper of the Privy Purse, who is responsible for monarchy's accounts, said of Frogmore Cottage: "The property had not been the subject of work for some years and had already been earmarked for renovation in line with our responsibility to maintain the condition of the occupied royal palaces estate.

"The Sovereign Grant covered the work undertaken to turn the building into the official residence and home of the Duke and Duchess of Sussex and their new family.

"The building was returned to a single residence and outdated infrastructure was replaced to guarantee the long-term future of the property.

"Substantially all fixtures and fittings were paid for by Their Royal Highnesses."

A royal source said the major work on the couple's cottage included replacing defective wooden ceiling beams and floor joists, outdated and inefficient heating systems were updated, the home needed substantial new electrical rewiring, including its own electrical sub-station, and new gas and water mains were installed.

Frogmore Cottage, which is owned by the Crown Estate, was a gift from Harry's grandmother, who was kept updated on the work.

The royal source said: "The Queen has been informed of the progress of the project, throughout the project."