Accounts posted online for the year ending March 2014 show record profits from Duchy.
The increase will give Queen Elizabeth a £2.4m increase, according to a Mirror report. The land of around 18,000 hectares in England and Wales was set up in 1399 to provide an income for the Sovereign.
At the end of March 2015, the Duchy of Lancaster had £472m of net assets under its control. These take the form of property and financial assets. The property assets are divided into rural estates, urban estates and development land.
"Revenues presented to the Sovereign are currently in the region of £16m per year," according to the Duchy of Lancaster's website.
In addition, the Duchy also owns a number of retail and business properties in a number of cities across England and Wales. It is the commercial ventures which are proving the most lucrative.
The Savoy Estate, part of the Duchy of Lancaster yields millions in commercial rents from the strip of land between Somerset House and the Savoy Hotel.
The Queen also receives an annual Sovereign Grant of around £37.9m which is from the Treasury, recently increased to £40.1million for the year ending March 2016, according to CNBC. The Crown Estate published its annual figures which declared a 6.7% rise in profit to £285m for 2014-15.
The Queen also has a huge collection of heirlooms, jewellery, art, and cars "the best collection of British and Commonwealth stamps in the world worth anything between £10 and £100 milllion, and the greatest private collection of jewellery in the world", David McClure, a former Reuters journalist and TV producer said in a Hampstead & Highgate Express article.
Such assets are gifted away before they incur inheritance tax. For example, the Queen Mother left her £35m art collection tax-free to the Queen which was then "transferred to the Royal Collection."
"The way the wealth is transferred as gifts by stealth means you can't trace it," says McClure.
On 8 July, Chancellor George Osborne imposed a 1% pay rise freeze on public sector workers, including nurses and teachers.