The wildlife charity that employs Carrie Johnson is facing further questions over its finances, after its latest accounts show it paid more than £150,000 in “interior design services” to the chairman’s wife last year.

The Aspinall Foundation, which is currently under investigation by the Charity Commission, took in just over £1,500,000 in donations from the public and corporate donors – while in the same year they paid £150,158 in fees to Victoria Aspinall, the wife of Damian Aspinall, the chairman of the charity’s trustees.

The transaction happened in 2020, which is before Carrie Johnson, the prime minister’s wife, took on a senior role at the charity heading up communications from January 2021.

The purpose of the Aspinall Foundation is global conservation work and releasing zoo animals back into the wild, working with its sister charity, the Howletts Wild Animal Trust, which runs two wild animal parks in Kent.

Damian Aspinall, the casino owner and socialite, is the son of the charity’s founder and its board of trustees includes Ben Goldsmith, the brother of government minister Zac Goldsmith, who is a friend of Carrie Johnson and the prime minister.

It solicits donations directly from the public, employing a team of fundraisers for the purpose, as well as running a fundraising lottery and asking for animals to be sponsored.

The chairman’s wife, Victoria Aspinall, had previously been paid £12,500 for interior design services in 2019, but her fees went up by more than tenfold in 2020 to a sum equivalent to 10% of donations taken that year. The charity also has large reserves in cash, property and fine art.

In its accounts, the Aspinall Foundation said the transaction was “at arms length” and added that the fees charged by Victoria Aspinall were “subject to a rigorous benchmarking exercise to ensure the foundation received value for money”.

The charity also paid £124,231 for accountancy work undertaken by Alvarium, a company of which another trustee, Charles Filmer, was a director.

In 2020 the foundation’s trustees, Damian Aspinall, Filmer, Robin Birley and Ben Goldsmith, secured a coronavirus business interruption loan of £2m, interest free for the first year. This was passed on in the form of a loan to the Howletts Wild Animal Trust.

The Aspinall Foundation’s previous set of accounts for 2019 showed the 30-room Howletts mansion in Kent owned by the charity was rented to Damian Aspinall for £2,500 a month. In 2020, he paid just over £10,000 a month for rent of the same mansion, after the rent was calculated based on an independent professional valuation.

The Aspinall Foundation was put under investigation by the Charity Commission over potential financial mismanagement in March this year. The matters being investigated by the commission pre-date Symonds’ appointment as an employee at the foundation, and there is no suggestion she is subject to its investigation.

At the time, the commission stressed that the opening of an inquiry is not a finding of wrongdoing. However, a statutory inquiry is its most serious form of investigation, undertaken only where it is seriously concerned that a charity is at risk of wrongdoing and abuse.

Where the commission concludes serious wrongdoing has taken place it has powers to remove trustees from the board, take over the running of the charity, or even wind it up.

A separate statutory inquiry was also announced into the management of Howlett’s Wild Animal Trust, which is also chaired by Aspinall, and whose trustees include Aspinall’s daughter Tansy.

The Aspinall Foundation did not respond to a request for comment. At the time of the Charities Commission investigation, a spokesperson for the foundation said: “The Aspinall Foundation remains firmly committed to its ethical and legal duties as a charitable body. Our trustees will continue to work openly and transparently with the Charity Commission to ensure best practice governance and compliance.”