The Queen has followed in the footsteps of her ancestors who once built giant earthworks to repel invaders.
But instead of keeping out enemy armies, she is trying to combat the 21st century menace of car drivers ruining the grass verges on her Sandringham estate.
Contractors have put up earth mounds known as bunds to prevent cars parking on the wide verges at the centre of the estate in Norfolk, and potentially turning them into a muddy quagmire in heavy rain.
The arrival of the bunds which are now grown over with grass coincided with the announcement that the estate plans to charge drivers for using its previously free car parks.
It is believed that the Queen’s staff had feared a big increase in the number of cars being left on verges, due to drivers trying to avoid the new charges.
The mounds present an obvious barrier to most cars which will force the drivers toward the two official car parks.
Regular visitors to the estate have furiously protested about the parking charges and have accused the 93-year-old Queen of profiteering from her subjects.
The car parks on the 20,000 acre estate have always been free up to now.
But many people used to park on the grass verges, so they could easily access walks in the woodland or enjoy picnics beside their cars.
Diggers were used to created the bunds on the verges either side of a 200 yard stretch of the road near St Mary Magdalene church where the Queen often worships, and the visitor centre.
They are similar to mounds of earth piled up alongside field in other parts of the country to keep out travellers.
The estate announced last October that car parking charges were being introduced as part of a re-development of visitor facilities. The charges are expected to be brought in over the next few weeks, but no date has yet been announced.
Motorists will charged £3 to park for up to two hours, £5 for up to four hours, and £7 all day if they want to walk in the woods, use play facilities or visit the estate shop or restaurant.
Anyone paying for admission to the museum, gardens or house when they are open during the summer months can avoid paying if they give their car registration number to staff at the ticket office.
Annual tickets costing £40 will also be available, offering unlimited parking and free admission to Sandringham House for the holder.
Details of penalties applied to anyone who fails to pay or overstays in the car park have not yet been revealed.
Sources on the estate suggest that drivers will have their number plates recorded by cameras as they enter and leave the car parks so that non-payers can be tracked down.
The estate has said that the re-development, which includes a revamped restaurant and shop, is necessary due to the number of visitors surging to more than 500,000 in 2018.
When the charges were announced, it was stated that they would help pay the ‘increasing cost of maintaining existing facilities’, and also ‘allow funding for future developments to improve the visitor experience’.
The estate said in October that it was ‘politely encouraging’ visitors to use the designated parking areas as opposed to the grass verges, which form part of the landscape.
The work includes the re-surfacing of the two car parks, more disabled bays, new lighting and improves paths.
Old conifer trees are being chopped down on the car parks to allow in more light, and a ‘more diverse’ range of trees planted to offer a ‘better habitat for wildlife’.
A poll of 1,900 people by the Lynn News local newspapers found that around three quarters said they would stay away from the estate rather than pay to park.
One social media user said: ‘Such a shame for the local people who like to walk their dogs round there!’
Another person criticised the Queen in a tweet, saying: ‘Astonishing. Sandringham is part of her personal wealth which is around £425M and she wants you to pay to park before you go shopping. Capitalism knows no bounds.’
It was initially announced that motorists would get 20 minutes free parking, but as a result of protests, the estate says that 30 minutes will be free instead.
Season ticket holders will also be able to get free parking for two cars instead of one and a ten per cent reduction in the gift shop.
A Buckingham Palace spokesperson said: ‘As was announced in October this year, Sandringham Estate is currently undergoing redevelopments with a view to offering improved facilities for visitors, while also maintaining the landscape and environment for all to enjoy.’